Electric tool

ABSTRACT

An electric tool, such as an angle driver, has a main tool body with a front portion and a rear portion positioned opposite to the front portion. The main tool body houses a motor configured to receive electricity to function as a drive source. A gear head is coupled with the front portion of the main tool body wherein the gear head has a spindle in communication with a motor axis of the motor via mesh-engagement of bevel gears associated with the motor axis. The spindle has with a cutter tool accessory attached thereto such that rotation of the motor axis produces a commensurate rotation of the cutter tool accessory. Battery attachment portions are associated with the rear portion of the main tool body and are configured to receive a corresponding set of batteries that provide electricity to power the motor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of application Ser. No. 14/807,291,filed Jul. 23, 2015, pending, which in turn is (1) a Continuation of PCTApplication No. PCT/JP2013/082964, filed Dec. 9, 2013, which claimspriority to Japanese Patent Application No. 2013-018881, filed Feb. 1,2013, and (2) a Continuation of PCT Application No. PCT/JP2013/084841,filed Dec. 26, 2013, which claims priority to Japanese PatentApplication No. 2013-018868, filed Feb. 1, 2013. The disclosure of theprior applications is hereby incorporated by reference herein in itsentirety.

TECHNICAL FIELD

The present invention generally relates to a hand-held electric toolsuch as an electric drill, i.e. an angle drill used for various types ofdrilling operations, and/or a disc grinder, which may be adapted togrind and/or machine a surface to produce a desired effect. Moreparticularly, the present invention may include various embodimentsdirected to the attachment and/or coupling of one or more batteriesadapted to engage with the electric tool such that the electric tool maybe easily maneuvered by hand during operation.

BACKGROUND ART

An electric tool, generally referred to in the art as an angle drill,may include a main tool body with a cylindrical motor housing thathouses an electric motor configured to operate as a drive source.Further, the cylindrical motor housing may also include a grip portionfor the convenience of a user and/or an operator, who may grasp the gripto operate the angle drill by hand. A gear head may be provided at afront end of the main tool body and provide structural support to aspindle to allow the spindle to rotate about an axis that is positionedorthogonal to (i.e. crossing and/or intersecting) a motor axis. Indetail, the spindle may mesh and/or engage with bevel gears associatedwith the motor axis to rotate as needed. Further, a specific type ofcutter tool accessory, such as a drill bit, may attach to the electrictool via connection to a chuck located at a distal end of the spindle.As discussed here, the electric tool may be hand-held, and may bemanufactured to be compact in height, i.e., in an axial direction of thespindle shaft, to be well suited for cases where drilling operation,screw tightening operation and/or the like must conducted in limitedspace. Moreover, a technique related to fabricating and/or using such anangle drill as described above may be generally disclosed in JapaneseLaid-Open Patent Publication No. 2004-34197.

The angle drill, in recent years, has developed to become cordless, andmay be configured to use a rechargeable battery as a power source,similar to other electric tools such as a battery-powered electricscrewdriver. The battery may have an output voltage adapted tocorrespond with a rated voltage of an electric motor included in themain tool body of the angle drill and/or electric tool, where theelectric motor may provide power as a drive source as discussed earlier.Accordingly, a battery with an output voltage of 36V may be selected foruse in conjunction with an electric motor with an identical ratedvoltage of 36V.

SUMMARY

Although 36V batteries may be desirable to power specific appliancesdemanding such a voltage, for example, such 36V batteries often costmore to produce and sell than other, more commonly available batterieswith lower output voltage ratings. For example, an 18V may be applied toa larger variety of electric-powered portable industrial tools than a36V battery. Also, a power tool user, such as an operator, may be morelikely to have access to 18V batteries, rather than the relatively rarer36V batteries, for example, the power tool user possesses a plurality ofthe 18V battery as spare batteries or the like.

An objective of the present invention is to enhance general usability ofan electric tool while reducing the associated battery cost for the sameby, for example, configuring the electric tool, such as an angle drilland/or a disc grinder, to accept multiple 18V batteries to providesimilar results as a traditional angle drill and/or a disc grinderrequiring, for example, a single 36V battery power source.

The electric tool of the present invention may include a main tool bodythat contains an electric motor configured to operate as a drive source.A gear head may be connected to a front of the main tool body and have aspindle with a cutter tool accessory attached thereto. In detail, thecutter tool accessory may be attached to the spindle so as to freelyrotate about an axis that is positioned orthogonal to a motor axis. Thespindle may mesh and/or engage with bevel gears associated with themotor axis of the electric motor such that rotation of the motor axismay translate to a commensurate rotation of the spindle. Further, aplurality of battery attachment portions, i.e. to which batteries mayattach to, as a power source, may be provided at a rear of the main toolbody.

In accordance with an embodiment of the present invention, an electrictool may be powered by an electric motor of a rated voltage thatcorresponds to a sum total of voltages of the batteries attached to theplurality of battery attachment portions. For instance, a 36Vspecification electric tool with an electric motor of a rated voltage of36V as a drive source may be driven by attaching two separate 18Vbatteries (which produce a combined output voltage of 36V).

As described above, an electric tool of a 36V specification may be usedwith two 18V batteries that a user may have as spare batteries, thusavoiding the need to obtain a single, dedicated 36V battery. Thus, anelectric tool of higher output, i.e. 36V, may be used with readilyaccessibly 18V batteries, thus potentially reducing the costs associatedwith purchasing the often rarer, and more expensive, 36V battery. As aresult, the convenience and/or usability of a high-output electric toolmay be enhanced.

In an embodiment, an electric tool has two battery attachment portions,each battery attachment portion directed to receive and/or connect witha corresponding battery, i.e. and 18V battery. Thus, as disclosed here,an electric tool of a high-output specification may have an electricmotor as a drive source, where the electric motor may be configured toaccept a rated voltage double the output voltage of the batteries.

In an embodiment, an electric tool has a plurality of battery attachmentportions, to which batteries may be attached, such that the longitudinaldirection of the plurality of battery attachment portions extendsvertically along a spindle axis. The batteries may be attached to and/ordetached from the plurality of battery attachment portions by slidingthe batteries vertically into their corresponding battery attachmentportions. Further, since the batteries may be attached in a lengthwisefashion with their longitudinal direction oriented vertically, theelectric tool may be relatively compact when viewed in a width-wisedirection.

In an embodiment, an electric tool to which batteries may attach, has aplurality of battery attachment portions allowing for batteries to bearranged side-by-side with respect to a motor axis. Since the batteriesmay be attached side-by-side with their longitudinal direction beingvertical, the electric tool may be relatively compact in the verticaldirection when compared to an instance where batteries are arrangedvertically and side-by-side.

In an embodiment, an electric tool has a plurality of battery attachmentportions to which batteries can be attached to and detached from bysliding the batteries in a vertical direction along a spindle axis. Thebatteries may be easily attached to and detached from the batteryattachment portions. In this respect, the electric tool may satisfyneeds associated with general operability and usability.

In an embodiment, an electric tool has a plurality of battery attachmentportions to which batteries may attach. The plurality of batteryattachment portions may have attachment surfaces oriented to face eachother. Thus, batteries may be attached to the plurality of batteryattachment portions in various orientations, i.e. horizontally and/orvertically. Such battery attachment flexibility as provided by theplurality of battery attachment portions may enhance operability and/orusability regarding attachment and detachment of the batteries to theircorresponding battery attachment portions.

In an embodiment, the electric tool in accordance with the presentinvention may include various means, such as two battery attachmentportions to which rechargeable batteries may be attached throughsliding, an electric motor configured to rotate a motor shaft byelectric power supplied from the rechargeable batteries, and a toolaccessory retaining portion driven by, for example, operation of themotor shaft. The two battery attachment portions may be respectivelyarranged on a housing that forms an exterior member in symmetry withrespect to an axis of the motor shaft.

Given that the electric power tool of the above-described embodimentincludes two battery attachment portions, two rechargeable batteries maybe inserted into their corresponding battery attachment portions to thusbe attached to the electric power tool. In such a configuration asdescribed here, power supplied to electric power tool may have arelatively high voltage and/or large supply capacitance when necessaryand/or desirable. As described earlier in connection with the electrictool in accordance with the first embodiment, the two battery attachmentportions may be respectively arranged on the housing that forms theexterior member in symmetry and/or alignment with respect to, forexample, a central axis of the motor shaft. This may achieve a balancein weight increased through the attached rechargeable batteries. Such anarrangement and/or configuration of the batteries on the housing asdescribed here, i.e. in sequence and/or in parallel, may allow foruniform weight distribution across the central axis of the motor shaftof the disc grinder, and thus suppress and/or reduce deterioration inthe maneuverability of the electric tool, while held in hand of anoperator and used to machine, for example, a surface.

In accordance with an embodiment of the present invention, an electrictool may include two battery attachment portions to which rechargeablebatteries may be attached through sliding, an electric motor configuredto rotate a motor shaft by electric power supplied from the rechargeablebatteries, and a tool accessory retaining portion driven by the motorshaft. The battery attachment portions are provided on a motor housingconfigured to support the electric motor.

In accordance with an embodiment of the present invention, an electrictool may include two battery attachment portions to which rechargeablebatteries may be attached through sliding, an electric motor configuredto rotate a motor shaft by electric power supplied from the rechargeablebatteries, and a tool accessory retaining portion driven by the motorshaft. Two battery attachment portions are provided on a housingconstituting an exterior member such that axes along which therechargeable batteries are attached through sliding may be positioned inparallel with each other.

In accordance with an embodiment of the present invention, an electrictool may include two battery attachment portions to which rechargeablebatteries may be attached through sliding, an electric motor rotating amotor shaft by electric power supplied from the rechargeable batteries,and a tool accessory retaining portion driven by the motor shaft. Thehousing constituting the exterior member may include a handle portiongenerally formed in a loop configuration. The battery attachmentportions are provided with respect to a part of the loop configuration.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a perspective view of an electric tool in accordancewith a first embodiment;

FIG. 2 illustrates a plan view of the electric tool in accordance withthe first embodiment, as seen in a direction of an arrow (II) in FIG. 1;

FIG. 3 illustrates a left side view of the electric tool in accordancewith the first embodiment, as seen in a direction of an arrow (III) inFIG. 1;

FIG. 4 illustrates a longitudinal sectional view of the electric tool inaccordance with the first embodiment taken along line (IV)-(IV) in FIG.2;

FIG. 5 illustrates a cross-sectional view of a battery attachmentportion taken along line (V)-(V) of FIG. 1;

FIG. 6 illustrates a perspective view of a battery;

FIG. 7 illustrates a plan view of the battery, as seen in a direction ofan arrow (VII) in FIG. 6;

FIG. 8 illustrates a rear view of the battery, as seen in a direction ofan arrow (VIII) in FIG. 6;

FIG. 9 illustrates a rear view of the battery attachment portion, asseen in a direction of an arrow (IX) in FIG. 1;

FIG. 10 illustrates a block diagram of an electric circuit;

FIG. 11 illustrates a perspective view of an electric tool in accordancewith a second embodiment;

FIG. 12 illustrates a plan view of the electric tool in accordance withthe second embodiment, as seen in a direction of an arrow (XII) in FIG.11;

FIG. 13 illustrates a right side view of the electric tool in accordancewith the second embodiment, as seen in a direction of an arrow (XIII) inFIG. 11;

FIG. 14 illustrates a rear view of the electric tool in accordance withthe second embodiment, as seen in a direction of an arrow (XIV) in FIG.11;

FIG. 15 illustrates a perspective view of an electric tool in accordancewith a third embodiment;

FIG. 16 illustrates a plan view of the electric tool in accordance withthe third embodiment, as seen in a direction of an arrow (XVI) in FIG.15;

FIG. 17 illustrates a right side view of the electric tool in accordancewith the third embodiment, as seen in a direction of an arrow (XVII) inFIG. 15;

FIG. 18 illustrates a rear view of the electric tool in accordance withthe third embodiment, as seen in a direction of an arrow (XVIII) in FIG.15;

FIG. 19 illustrates a perspective view of an electric tool in accordancewith a fourth embodiment;

FIG. 20 illustrates a plan view of the electric tool in accordance withthe fourth embodiment, as seen in a direction of an arrow (XX) in FIG.19;

FIG. 21 illustrates a right side view of the electric tool in accordancewith the fourth embodiment, as seen in a direction of an arrow (XXI) inFIG. 19;

FIG. 22 illustrates a rear view of the electric tool in accordance withthe fourth embodiment, as seen in a direction of an arrow (XXII) in FIG.19;

FIG. 23 illustrates a perspective view of an electric tool in accordancewith a fifth embodiment;

FIG. 24 illustrates a plan view of the electric tool in accordance withthe fifth embodiment, as seen in a direction of an arrow (XXIV) in FIG.23;

FIG. 25 illustrates a right side view of the electric tool in accordancewith the fifth embodiment, as seen in a direction of an arrow (XXV) inFIG. 23;

FIG. 26 illustrates a rear view of the electric tool in accordance withthe fifth embodiment, as seen in a direction of an arrow (XXVI) in FIG.23;

FIG. 27 illustrates a perspective view of an electric tool in accordancewith a sixth embodiment;

FIG. 28 illustrates a plan view of the electric tool in accordance withthe sixth embodiment, as seen in a direction of an arrow (XXVIII) inFIG. 27;

FIG. 29 illustrates a right side view of the electric tool in accordancewith the sixth embodiment, as seen in a direction of an arrow (XXIX) inFIG. 27;

FIG. 30 illustrates a rear view of the electric tool in accordance withthe sixth embodiment, as seen in a direction of an arrow (XXX) in FIG.27;

FIG. 31 illustrates a perspective view of an electric tool in accordancewith a seventh embodiment;

FIG. 32 illustrates a plan view of the electric tool in accordance withthe seventh embodiment, as seen in a direction of an arrow (XXXII) inFIG. 31;

FIG. 33 illustrates a right side view of the electric tool in accordancewith the seventh embodiment, as seen in a direction of an arrow (XXXIII)in FIG. 31;

FIG. 34 illustrates a rear view of the electric tool in accordance withthe seventh embodiment, as seen in a direction of an arrow (XXXIV) inFIG. 31;

FIG. 35 illustrates a perspective view of an electric tool in accordancewith an eighth embodiment;

FIG. 36 illustrates a plan view of the electric tool in accordance withthe eighth embodiment, as seen in a direction of an arrow (XXXVI) inFIG. 35;

FIG. 37 illustrates a right side view of the electric tool in accordancewith the eighth embodiment, as seen in a direction of an arrow (XXXVII)in FIG. 35;

FIG. 38 illustrates a rear view of the electric tool in accordance withthe eighth embodiment, as seen in a direction of an arrow (XXXVIII) inFIG. 35;

FIG. 39 illustrates a perspective view of an electric tool in accordancewith a ninth embodiment in a configuration where a leg erects withrespect to a tool body;

FIG. 40 illustrates a perspective view of the electric tool inaccordance with the ninth embodiment in a configuration where a leg ispositioned in an erect position with respect to a main tool body;

FIG. 41 illustrates a plan view of the electric tool in accordance withthe ninth embodiment in a configuration where the leg is positioned inthe erect position with respect to the main tool body;

FIG. 42 illustrates a longitudinal sectional view of a tiltable supportportion of the leg taken along line (XXXXII)-(XXXXII) in FIG. 41;

FIG. 43 illustrates a side view of the electric tool in accordance withthe ninth embodiment in a configuration where the leg is positioned inthe erect position with respect to the main tool body;

FIG. 44 illustrates a longitudinal sectional view of the electric toolin accordance with the ninth embodiment in a configuration where the legis positioned in the erect position with respect to the main tool body;

FIG. 45 illustrates a cross-sectional view of the tiltable supportportion of the leg taken along line (XXXXV)-(XXXXV) in FIG. 44;

FIG. 46 illustrates a front view of a battery base taken along line(XXXXVI)-(XXXXVI) in FIG. 44;

FIG. 47 is a side view of a disc grinder in accordance with a firstembodiment;

FIG. 48 is a cut-away view illustrating an inner structure of the discgrinder of FIG. 47;

FIG. 49 is a plan view, as seen from below, of the disc grinder of FIG.47;

FIG. 50 is a plan view, as seen from behind, of the disc grinder of FIG.47;

FIG. 51 is a perspective view of a rechargeable battery attached to abattery attachment portion through sliding;

FIG. 52 is an enlarged plan view of portion (LII) of FIG. 49,illustrating a battery terminal connection portion;

FIG. 53 is a conceptual circuit diagram illustrating the circuitstructure of an electric motor schematically and conceptually;

FIG. 54 is a side view of a disc grinder in accordance with a secondembodiment;

FIG. 55 is a plan view, as seen from below, of the disc grinder of FIG.54;

FIG. 56 is a plan view, as seen from behind, of the disc grinder of FIG.54;

FIG. 57 is a side view of a disc grinder in accordance with a thirdembodiment;

FIG. 58 is a plan view, as seen from below, of the disc grinder of FIG.57;

FIG. 59 is a plan view, as seen from behind, of the disc grinder of FIG.57;

FIG. 60 is a side view of a disc grinder in accordance with a fourthembodiment;

FIG. 61 is a plan view, as seen from below, of the disc grinder of FIG.60;

FIG. 62 is a plan view, as seen from behind, of the disc grinder of FIG.60;

FIG. 63 is a side view of a disc grinder in accordance with a fifthembodiment;

FIG. 64 a plan view, as seen from top, of the disc grinder of FIG. 63;and

FIG. 65 is a plan view, as seen from behind, of the disc grinder of FIG.63.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

Next, a first through ninth embodiments of the present invention will bedescribed with reference to FIGS. 1 through 46. In detail, in the firstthrough eighth embodiments, an electric tool 1, such as an angle drill,in which a spindle axis (output axis) is configured to cross, engageand/or mesh with a motor axis is described in further detail. As shownin FIGS. 1 through 4, the electric tool 1 of the first embodiment has amain tool body 10 with a main body housing 11 that contains an electricmotor 12 that may be configured to be powered by electric current havinga rated voltage of 36V, further where the electric motor 12 may functionas a drive source, a gear head 20 connected to a front portion of themain tool body 10, and two battery attachment portions 30 formed at arear portion of the main tool body 10. In detail, batteries 31 mayinsert into and attach with their corresponding battery attachmentportions 30. The main tool body 10 may be of a cylindrical configurationwith a suitable diameter, i.e. such that the main tool body 10 may beeasily grasped and/or held by a user, such as an operator. In theconfiguration shown in FIGS. 1 through 4, the main tool body 11 mayfunction as and/or provide a grip to be grasped by a user. For instance,a user may be positioned within a vicinity of the main tool body 10 andgrasp the main tool body 10 with, for example, either a right handand/or a left hand. The relative directions of front-rear, right-left,upper, and lower may be defined from the perspective of a user of theelectric tool 1 and may be shown in a key and/or a legend in the FIGS.Further, the directions described above may be used in the followingdescription to describe the spatial orientation, connection and/orconfiguration of various parts, elements, members and/or components ofthe electric tool 1, etc.

As shown in FIG. 4, the electric motor 12 may transmit a rotationaloutput to a drive shaft 15 via mesh-engagement of a drive gear 13,attached to an output shaft 12 a, and an intermediate gear 14. In FIG.4, reference numeral 12 b may indicate a carbon brush. A driving sidebevel gear 21 is integrally formed at a distal end of the drive shaft15. The driving side bevel gear 21 may mesh with a driven side bevelgear 22 which may be fixed to and/or in communication with a spindle 23.A gear head housing 26 may support the spindle 23 via bearings 24 and 25such that the spindle 23 may rotate relative to the gear head housing26. A rotational axis (spindle axis) of the spindle 23 may be positionedorthogonal to a rotational axis (i.e., a motor axis) of the output shaft12 a of the electric motor 12 and rotate as a result of engagementand/or meshing of the driving side bevel gear 21 and the driven sidebevel gear 22. A chuck 27 for attaching a cutter tool accessory such asa drill bit (not shown in the FIGS.) may be formed integrally with thespindle 23 at a distal end of the spindle 23. A lower portion of thechuck 27 protrudes downwardly from the gear head housing 26. The cuttertool accessory attached to the spindle 23 via the chuck 27 may rotatearound the spindle axis to, for example, perform a drilling operationwhen driven by the electric motor 12. In the electric tool 1, i.e.herein also referred to as an “angle drill”, a height dimension H may bemeasured from a distal end of the cutter tool accessory to an uppersurface of the gear head 20. Further, the height dimension H, asdescribed here, may be relatively short and/or compact to betteraccommodate drilling and/or operation of the electric tool in, forexample, difficult to reach areas and/or crevices. Moreover, such aconfiguration as described here may allow for the efficient performanceof a drilling operation in a space of a relatively short height, asmeasured in a vertical direction in the FIGS.

Referring generally to FIG. 4, a battery base 32 may be formed as aplate and be integrally with the main body housing 11 at a rear portionof the main body housing 11. In the first embodiment, the battery base32 may be configured within the main body housing 11 to extend, i.e.,substantially symmetrically, in the right-to-left direction. Asdescribed below, the battery base 32 may be an attachment seat portionconfigured to receive and/or attach to two batteries 31, and the batterybase 32 may prevent a hand of the user from, for example, inadvertentlysliding and/or slipping on the main tool body 10. Also, the battery base32 may contain a controller board C that may primarily control theelectric motor 12.

Two battery attachment portions 30 may be formed on a rear surface ofthe battery base 32. The battery attachment portions 30 are illustratedin further detail in FIG. 9. The battery attachment portions 30, asshown in the FIGS., include a right battery attachment portion 30 and aleft battery attachment 30 where right and left battery attachmentportions 30 are of the same configuration. Further, each batteryattachment portion 30 includes a pair of right and left rail portions 30a. The rail portions 30 a may be arranged to extend vertically and bepositioned parallel to each other. Positive and negative connectionterminals 30 b and 30 c may be arranged between the two rail portions 30a. Further, the positive and negative connection terminals 30 b and 30 care also vertically elongated and parallel to each other. An engagementrecess 30 d into which a lock claw portion 31 e (See FIG. 8) of thebattery 31 may be fitted is formed at a top portion of the batteryattachment portion 30.

Each of the FIGS. 6 through 8 illustrates a battery 31, i.e. of thebatteries 31. The battery 31 may be inserted into and attach to acorresponding right or left battery attachment portions 30. In anembodiment, the battery 31 may be a lithium ion battery with an outputvoltage of 18V. The each battery 31 may have a battery case formed as,for example, a parallelepiped defined by the following relativedimensions: length X>width Y>height Z. Further, a battery case of thebattery 31 may be configured to contain and/or house a plurality ofbattery cells. Moreover, the battery 31 may be repeatedly used toprovide power to the electric tool 1 as needed by, for example, removalfrom the battery attachment portion 30, charge by a dedicated batterycharger, and re-insertion to the battery attachment portion 30post-charging to once again power the electric tool 1.

The 18V battery 31 may be attached to and/or detached from the batteryattachment portion 30 through sliding along a pair of right and leftrail receiving portions 31 a formed on an upper surface thereof. Indetail, the 18V battery 31 may be a slide-attachment type battery, theupper surface of which may be superimposed on, i.e. lined up against,the battery attachment portion 30 to attach to and/or connect with thebattery attachment portion 30.

As shown in FIGS. 6 and 7, the pair of right and left rail receivingportions 31 a and positive and negative terminal receiving portions 31 band 31 c may be arranged on an upper surface of the 18V battery 31. Whenthe battery is viewed as a single unit, the pair of right and left railreceiving portions 31 a may extend outwardly in a front-to-reardirection (i.e., longitudinal direction; and/or when the battery 31 isinserted and/or attached to a corresponding battery attachment portion30, the pair of right and left rail receiving portions 31 a may extendin a vertical direction) and also be arranged parallel to each other.The terminal receiving portions 31 b and 31 c may be arranged to extendalong an inner side of the right and left rail receiving portions 31 a.A connector 31 d, which may be connected to a charger (not shown in theFIGS.), may be arranged between the terminal receiving portions 31 c andsubstantially positioned at the center of the upper surface of thebattery 31. Further, in an embodiment, various control signals may beboth transmitted and received between the battery 31 and a chargerduring charging through the connector 31 d.

The lock claw portion 31 e may be provided at a rear portion of theupper surface of the battery 31. A spring incorporated into the batterycase may bias the lock claw portion 31 e to protrude, for example,upwardly. The lock claw portion 31 e may reversibly deform, uponreceiving an external force and/or pressure, for example, to elasticallyfit into the engagement recess 30 d of the battery attachment portion30. Accordingly, the attachment state of the battery 31 may be lockedand/or fixed in position with respect to the battery attachment portion30.

As shown in FIGS. 7 and 8, an unlock switch and/or an unlock button 31 fmay be provided to and/or on a rear surface of the battery 31. In anembodiment, the unlock button 31 f may be formed integrally, i.e. as asingle, uniform piece, with the lock claw portion 31 e. Thus, should theunlock button 31 f be compressed and/or depressed by a fingertip of auser and/or operator of the electric tool 1, the lock claw portion 31 emay be withdrawn and/or retracted downwards, i.e. opposed to and/oragainst the biasing force of the spring. The lock claw portion 31 e maybe retracted to the unlock position below and removed from theengagement recess 30 d. Thus, the battery 31 may then be detached fromthe battery attachment portion 30 by, for example, sliding the battery31 in a detaching direction.

Referring generally now to FIGS. 1, 3 and 4, a switch lever 16 may beattached on a lower surface of the main tool body 10 such that, when auser pulls the switch lever 16 with a fingertip of his or her hand,i.e., grasping the main tool body 10, a switch rod 17 a may be upwardlypushed in to thus activate a main switch 17. Further, anormal-to-reverse directional switching lever 18 to switch therotational direction of the electric motor 12 may be positioned abovethe switch lever 16.

Referring generally now to FIG. 10, when a main switch 17 is activated,electricity may be supplied to a power circuit 40 to thus activate. Thetwo batteries 31 may be attached to the right and left batteryattachment portions 30 to be electrically connected in series. As aresult, the two 18V batteries 31, connected to each other in a series,may be connected to the power circuit 40 to provide a total, i.e.combined, power source with a total output voltage of 36V. A controllerboard C, configured to primarily control the electric motor 12, may beincorporated into the power circuit 40 as shown in FIG. 10. Further, amicroprocessor 42 for control, a FET (switching element) 43, etc. may bemounted on the controller board C.

Accordingly, the electric motor 12 may function as a drive source with arated voltage of 36V, i.e. such that the electric motor 12 may beconfigured to operate with electric current of a 36V voltage. In detail,the two 18V batteries 31 connected in series may combine to provide atotal system voltage of 36V to drive the electric motor 12 as needed.Thus, the electric tool 1 of a 36V specification may be powered by two18V batteries 31 connected in series, as described here, as the powersource.

Returning now to that shown by FIGS. 1, 3 and 4, a protrusion 19extending downwardly may be formed at a front portion of a lower surfaceof the main body housing 11. The protrusion 19 may be formed to includean illumination device (LED) 19 a, which may be activated simultaneouslyalong with the activation of the electric motor 12 by, for example,pulling of the switch lever 16. Further, the illumination device (LED)19 a may be turned off, i.e. extinguished simultaneously with stoppingof the electric motor 12 by releasing pressure against the switch lever16, i.e. such that the switch lever 16 may decompress to return to anoriginal and/or natural disengaged and/or deactivated position. Theportion around the cutter tool accessory (i.e. the portion beingmachined) may be illuminated brightly by the illumination device 19 ato, for example, illuminate a vicinity of the electric tool 1 toefficiently perform a drilling operation and/or the like in a dimly-litarea. Further, the protrusion 19 may also assist in preventinginadvertent and/or accidental activation of the switch lever 16 when theelectric tool 1 is placed on a work-bench or the like.

The first through eighth embodiments described herein may differ fromeach other in, for example, attachment positions, attachment orientationand/or attachment/detachment direction of the two batteries 31.Nevertheless, the first through eighth embodiments may be identical withregard to basic formative components of the electric tool 1 such as themain tool body 10 and/or the gear head 20. Accordingly, like componentsare indicated by like reference numerals, and a description of the samewill thus be omitted. In the drawings, symbol F indicates the frontsurface, symbol B indicates the rear surface, symbol L indicates theleft-hand side surface, symbol R indicates the right-hand side surface,symbol U indicates the upper surface (attachment surface), and symbol Dindicates the lower surface of the battery to make it clear whichsurface of the battery 31 is visible. This helps to clarify theattachment orientation, the attachment/detachment direction, and thearrangement state, i.e. being attached or detached, of the two batteriesin the drawings.

As shown in FIGS. 1 through 5, in the first embodiment, the twobatteries 31 may be positioned side-by-side, in a longitudinal statelongitudinal direction of each battery 31 of the batteries 31 (i.e. thefront-rear direction for each battery) may be oriented vertically. Asindicated by the hollow arrows in FIGS. 1 and 3, the attachmentdirection of the two batteries 31 may be generally downward. Each of thebatteries 31 may be attached to the battery attachment portion 30 bysliding downwards while also causing the rail portions 30 a of thebattery attachment portion 30 to enter, i.e. slide into to engage with,for example, the corresponding rail portions 31 a of the batteryattachment portion 30, with the front surface F facing downwards. Whenthe battery 31 reaches the slide insertion and/or engagement end withrespect to the battery attachment portion 30 a, the lock claw portion 31e may reversibly deform to be elastically fitted into the engagementrecess 30 d, whereby the battery 31 may then be locked in the attachedposition.

In the first embodiment, both batteries 31 may be attached in alengthwise orientation in which the longitudinal direction of eachbattery 31 of the batteries 31 extends vertically. Alternatively put,upon successful insertion and/or engagement of the batteries 31 withtheir corresponding battery attachment portions 30, the rear surfaces Bmay be directed upwards as shown in FIG. 1.

To remove and/or detach the battery 31 from the battery attachmentportion 30, a user of the electric tool 1 may depress the unlock button31 f with his or her fingertip to retract the lock claw portion 31 e outof the engagement recess 30 d. As a result, the battery may becomeupwardly slidable and can now be detached from the battery attachmentportion 30.

Referring now to FIGS. 11 through 14, an electric tool 2 in accordancewith the second embodiment is shown. In the second embodiment, theattachment direction of the two batteries 31 may be generally oppositeto that of the first embodiment, i.e. in that the batteries 31 slide indown-to-up direction. In detail, in the second embodiment, the batteries31 may be attached to the two battery attachment portions 30 formed onthe battery base 33 through upward sliding where the front surfaces F ofthe batteries 31 are pointed upwards. The two batteries 31 may beattached in a lengthwise orientation in which the longitudinal directionof each battery of the batteries 31 extends along the vertical directionsuch that the front surfaces F of each battery 31 of the batteries 31face upwards while arranged side-by-side. The battery base 33 may beformed at the rear of the main tool body 10 and extend in a width-wisedirection from right-to-left. Two battery attachment portions 30 may bearranged on the rear surface of the battery base 33 in a directionvertically reversed when compared to that shown by the first embodiment(i.e. as illustrated in FIG. 9). In detail, as shown in FIGS. 11, 13,and 14, the attachment direction of the two batteries 31 may begenerally upward, with the front surfaces F thereof facing upwards whileattached to the corresponding battery attachment portions 30. Thebattery base 33 of the second embodiment also includes the controllerboard C, which configured to primarily control the electric motor 12.

As described and discussed above in connection with the first and secondembodiments, the two batteries 31 are attached in an orientation inwhich their longitudinal direction (i.e., the length-wise X direction)extends in the vertical direction while arranged side-by-side (twice thedistance of width Y). Accordingly, such a placement and/or configurationas described here may be relatively compact in the horizontal directionwhen compared to a construction where the two batteries 31 may beattached in an orientation in which their width Y direction extendsvertically while arranged side-by-side (twice the distance of length X).As described here, the two batteries 31 may be attached to thecorresponding battery attachment portions 30 while arrangedside-by-side. As shown in FIGS. 3 and 13, sizes of attachment space forthe two batteries 31 in the vertical direction and the longitudinaldirection are big enough of sizes of one battery in those directions.Such a compact configuration as described here may allow for drillingoperation to be performed efficiently in a relatively tight space.

Referring now to FIGS. 15 through 18, an electric tool 3 in accordancewith the third embodiment is shown. In the electric tool 3 of the thirdembodiment, the two batteries 31 may be attached in a lengthwiseorientation in which the longitudinal direction of each battery 31extends in the vertical direction while arranged vertically, i.e. whereone battery is oriented above and/or on top of the other, as shown in atleast FIG. 15 side-by-side. Also, in the third embodiment, a batterybase 34 may be formed at the rear of the main tool body 10 and protruderelatively further in the vertical direction than in the horizontaldirection. The two battery attachment portions 30 may be arranged at anupper and lower portion of a rear surface of the battery base 34,respectively. The battery attachment direction of the upper batteryattachment portion 30 may be relatively downward (i.e. the samedirection as that shown in FIG. 9), and the battery attachment directionof the lower battery attachment portion 30 may be diametrically opposedto the attachment direction of the upper battery attachment portion 30to be positioned upward (i.e. vertically reverse to the direction asshown in FIG. 9). Thus, as indicated by hollow arrows in FIG. 15, theattachment direction of the upper battery 31 may be downward, and theattachment direction of the lower battery 31 may be upward.

As shown in FIG. 15, the battery 31, i.e. any one of the batteries 31,may be attached to the upper battery attachment portion 30 in a downwardlengthwise orientation where the front surface F of the battery 31 isdirected downwards. Conversely, the other battery 31, i.e. the remainingbattery of the batteries 31, may be attached to the lower batteryattachment portion 30 in an upward lengthwise orientation where thefront surface F of the battery 31 is directed upwards. Further, the twoupper and lower batteries 31 are attached while arranged verticallyside-by-side such that their front surfaces F are opposed, i.e. faceeach other.

The battery base 34 of the third embodiment also includes the controllerboard C, which is configured to primarily control the electric motor 12.In the third embodiment, the two batteries 31 may be attached whilearranged vertically side-by-side, and/or with one battery 31 positionedabove and/or on top of the other, depending on the perspective of a userof the electric tool 1, with their width Y direction extending in thehorizontal direction. Thus, as shown in FIG. 16, the configurationand/or orientation of the batteries 31 as described in connection withthe third embodiment need only occupy the width of one battery in theright-to-left direction. Further, such a configuration may allow for theperformance of a drilling operation efficiently in a relatively tightspace, especially where room in the right-to-left direction is lacking.

Referring now to FIGS. 19 through 22, an electric tool 4 in accordancewith the fourth embodiment is shown. In the fourth embodiment, the twobatteries 31 may be attached to the corresponding batter attachmentportions 30 in a lengthwise orientation in which the batteries may bepositioned to face each other in the horizontal direction. A batterybase 35 may be formed at the rear of the main tool body 10 and configureto extend backwards, i.e. away from the chuck 27. The battery attachmentportions 30 may be arranged to extend along right and left sides of thisbattery base 35. The battery attachment portions 30 may be arranged suchthat the battery attachment direction generally upward (verticallyreverse to the direction as shown in FIG. 9), with engagement recesses30 d situated at the lower positions on the battery attachment portions30. As indicated by the hollow arrows in the drawing, the attachmentdirection of the batteries 31, with respect to the battery attachmentportions 30 may be upward. In detail, the batteries 31 may be attachedto the battery attachment portions 30 by upwardly sliding the batteries31 with respect to the battery attachment portions 30. As shown in thedrawings, the batteries 31 may be attached in a lengthwise orientationin which longitudinal direction of the battery 31 may extend in thevertical direction, i.e. and in an upward lengthwise orientation inwhich their front surfaces F are directed upwards.

Moreover, the two right and left batteries 31 may be attached to thecorresponding battery attachment portions 30 in a lengthwise orientationwhere the upper surfaces U of the batteries 31 face each other as shownin FIG. 19.

Referring now to FIGS. 23 through 26, an electric tool 5 in accordancewith the fifth embodiment is shown. The fifth embodiment may differ fromthe fourth embodiment in that the attachment directions of the twobatteries 31 may be opposite each other. Similar to that shown in thefourth embodiment, a battery base 36 may be formed toward and/or at therear of the main tool body 10 and may protrude backwards, i.e. away fromthe chuck 27. The battery attachment portions 30 may be positionedand/or arranged to extend along right and left sides of the battery base36. Further, the right and left battery attachment portions may bearranged to face each other, i.e. to be opposite each other along avertical and/or longitudinal direction. Thus, as indicated by the hollowarrows in the drawings, the attachment direction of the left-hand sidebattery 31 may be downward. Conversely, the attachment direction of theright-hand side battery 31 may be upward. The battery 31 attached to theleft-hand side battery attachment portion 30 may be attached in adownward lengthwise orientation such that a rear surface B thereof mayface upwards as shown in FIG. 23. Also, battery 31 attached to theright-hand side battery attachment portion 30 may be attached in anupward lengthwise orientation such that the front surface F thereof mayface upwards. Moreover, the right-hand side and left-hand side batteries31 may be attached in a longitudinal and/or lengthwise orientation suchthat their upper surfaces U face each other.

In accordance to that shown in both the fourth and fifth embodiments,the two batteries 31 may be attached to the corresponding batteryattachment portions 30 such that the height Z direction of each battery31 extends horizontally such that two batteries 31 may face each otherwhen viewed in a right-to-left direction. Thus, the weight of the twobatteries 31 may be balanced across a center axis spanning the length ofthe electric tool 1. Further, the configuration shown by the fourth andfifth embodiments may allow for the electric tool 1 to be relativelycompact in the vertical direction, the horizontal direction, and thefront-to-rear direction.

Referring now to FIGS. 27 through 30, an electric tool 6 in accordancewith the sixth embodiment is shown. In the sixth embodiment, the batteryattachment portions 30 may be arranged at right-hand side and left-handside of a battery base 37 formed at the rear of the main tool body 10,i.e. away from the chuck 27. Moreover, the battery attachment portions30 may be arranged horizontally such that their attachment/detachmentdirection extends along the front-to-rear direction of the main toolbody 10. Thus, the two batteries 31 may be inserted and attached to thecorresponding battery attachment portions 30 in a forward lateralorientation. In detail, the longitudinal direction of the two batteries31 may extend in the front-to-rear direction of the main tool body 10where the front surfaces F of the two batteries 31 may be directedtoward the front of the main tool body 10 as shown in FIG. 27. Further,the two batteries 31 may be attached in a lateral orientation such thattheir upper surfaces U face each other.

As indicated by the hollow arrows in FIGS. 27 through 30 both thebatteries 31 are inserted into and attach with the corresponding batteryattachment portions 30 in a forward-facing direction, i.e. toward thechuck 27. Thus, the two batteries 31 may be attached to the batteryattachment portions 30 such that the back surfaces B of the batteries 31may be directed toward a rear of the electric tool 1, i.e. away from thechuck 27.

Further, and in accordance with the sixth embodiment the sixthembodiment, the two batteries 31 may be attached such that thelongitudinal direction (i.e. the length-wise X direction) extends alongthe front-to-rear direction of the electric tool 1 and that the twobatteries 31 may be positioned to face each other, i.e. in a generallyhorizontal configuration as shown in FIG. 27. Also, and as shown in FIG.29, a size of attachment space for the batteries in the verticaldirection may require only the size of one battery in the verticaldirection. The lateral and/or horizontal configuration of the twobatteries 31 allows for the electric tool 1 to occupy a relativelysmaller volume than that shown by earlier embodiments, i.e. where thebatteries 31 were attached in an upright and/or longitudinal direction.The horizontal configuration shown by the sixth embodiment may allow theelectric tool 1 to perform a drilling operation efficiently in a spacewhich is relatively small in, for example, the vertical direction.

Referring now to FIGS. 31 through 34, an electric tool 7 in accordancewith the seventh embodiment is shown. Reviewing that discussed earlierfor the sixth embodiment, the two batteries 31 may be horizontallyattached in a forward lateral orientation such that their upper surfacesU face each other. In contrast, the seventh embodiment differs from thesixth embodiment with regard to the orientation of the attachment of thetwo batteries 31 to the corresponding battery attachment portions 30relative to the electric tool 1. Specifically, as shown here for theseventh embodiment, the two batteries 31 may be arranged vertically,i.e. with one battery 31 above the remaining battery 31. Further, thebatteries 31 may be inserted into and/or attached with the correspondingbattery attachment portions by sliding in, for example, a forwarddirection and such that the upper surfaces U of the batteries face eachother as shown in FIG. 31.

The battery attachment portions 30 may be arranged respectively on theupper and lower surfaces of a battery base 38 formed toward and/or atthe rear of the main tool body 10, i.e. away from the chuck 27. As inthe sixth embodiment, the two battery portions 30 may be arranged suchthat the attachment orientation and/or direction of the batteries 31 maybe forward. Thus, the seventh embodiment may correspond to aconstruction obtained by displacing and/or rotating the battery base 37by 90 degrees about the motor axis, i.e. to rotate both the batteries 31and the battery attachment portions 30 from that shown by the sixthembodiment to that shown by the seventh embodiment.

The two batteries 31 may be inserted into and attached to the batteryattachment portions 30 by sliding forward as indicated by hollow arrowsin FIGS. 31 through 33 in an orientation such that the longitudinaldirection of the two batteries 31 extends in the front-to-reardirection. Thus, in an attached condition, the back faces B of the upperand lower batteries 31 may be directed backwards.

In accordance with the seventh embodiment, the two batteries 31 may beattached to face each other vertically, with the longitudinal direction(i.e., length X direction) of the batteries 31 extending in thefront-to-rear direction as shown in FIGS. 31 through 33. Further, asshown in FIG. 32, a size of attachment space for the batteries in theright-to-left direction may require only the size of one battery whenviewed in the right-to-left direction. Such a configuration as describedhere may allow for the efficient performance of a drilling operation ina relatively small and/or tight space in the right-to-left direction.

The battery bases 35 through 38 of the fourth through seventhembodiments described above may also include the controller board C,which may be configured to primarily control the electric motor 12, i.e.activating and/or deactivating the electric motor 12. As shown in FIG.31 illustrating the seventh embodiment, intake ports 38 a may be formednear and/or in rear surfaces of the battery bases 35 through 38 of thefourth through seventh embodiments. Further, the intake ports 38 a mayreceive air from outside the electric tool and redirect the air withinthe electric tool 1 as indicated by the dashed-line arrows in thedrawing. In detail, the air may flow toward the main tool body 10 tocool the electric motor 12. The controller board C may be arranged at,for example, a midpoint of the route taken by air traveling to the motorsuch that the controller board C is also cooled by the air.

Referring now to FIGS. 35 through 38, an electric tool 8 in accordancewith the eighth embodiment is shown. In detail, aspects of the eighthembodiment may generally correspond to that shown and discussed earlierin connection with at least the first embodiment and the secondembodiment. Specifically, the two batteries 31 may be attached in alongitudinal and/or lengthwise orientation in which the longitudinaldirection (i.e., length-wise X direction) of the batteries 31 extends inthe vertical direction while the batteries 31 are arranged horizontally,i.e. side-by-side. With regard to the attachment direction of thebatters 31, both of two batteries 31 may be attached downwardly in thefirst embodiment. In contrast, both of two batteries 31 may be attachedupwardly in the second embodiment. In comparison to that shown anddiscussed for both the first and second embodiments, the eighthembodiment allows for one of the two batteries 31 to be attached in anupward direction, while the remaining battery of the two batteries 31may be attached in a downward direction.

Specifically, in the eighth embodiment, the left-hand side battery 31 ofthe two batteries 31 may slide into and thus be attached to acorresponding battery attachment portion 30 in a downward lengthwiseorientation. In comparison, the right-hand side battery 31 may besimilarly attached to a corresponding battery attachment portion 30, butby sliding in an upward lengthwise orientation. Thus, as indicated bythe hollow arrows in the drawing, the attachment direction of theleft-hand side battery 31 may be downward, and the attachment directionof the right-hand side battery 31 may be upward. Accordingly, whileattached to their corresponding battery attachment portions 30, the rearsurface B of the left-hand side battery 31 and the front surface F ofthe right-hand side battery 31 may be facing and/or directed upwards.

Similar to the first and second embodiments, a battery base 39 may beformed near and/or at the rear of the main tool body 10 to extend inboth right and left directions. The battery base 39 may also beconfigured to include the controller board C, which may be configuredprimarily to control the electric motor 12. Two battery attachmentportions 30 may be arranged on a rear surface of the battery base 39 tobe arranged horizontally, i.e. side-by-side. Although not shown in theFIGS., the left-hand side battery attachment portion 30 may be arrangedsuch that the engagement recess 30 d thereof is located on an upper partof the battery attachment portion 30 (i.e., the same orientation asshown in FIG. 9), whereas the right-hand side battery attachment portion30 may be arranged such that the engagement recess 30 d thereof islocated on a lower part of the battery attachment portion 30.

Similar to the first and second embodiments, the two batteries 31, inaccordance with the eighth embodiment, may be attached such that thelongitudinal direction (i.e. the length X direction) of the batteries 31extends along the vertical direction while arranged horizontally, i.e.side-by-side (i.e. twice the size of width Y). Such a configuration maybe relatively compact when viewed in the right-to-left direction whencompare to a configuration where the batteries 31 may be attached in ahorizontal orientation such that their width Y direction extends alongthe vertical direction while arranged horizontally, i.e. side-by-side(i.e. twice the size of length X). Similar to that shown and discussedfor the first and second embodiments, the two batteries 31 may beattached while arranged horizontally, i.e. side-by-side. Further, thesizes of the space occupied by the batteries 31 in the verticaldirection and the longitudinal direction may require only the sizes,i.e. the dimension, of one battery of the batteries 31 in thosedirections, as shown in FIG. 37. Such a configuration of the batteries31 as disclosed by the eighth embodiment may allow for drillingoperation to be performed efficiently in a relatively tight space spacesand/or confines especially along the vertical direction (i.e. the axialdirection of the drill bit) or relatively small space at the rear of theelectric tool 1.

Referring now to FIGS. 39 through 46, an electric tool 9 in accordancewith the ninth embodiment is shown. In detail, the electric tool 9 ofthe ninth embodiment may differ from the electric tool 1 of the firstembodiment with regard to the inclusion of several additional, uniquefeatures, such as a tiltable leg portion 50 at a rear of the main toolbody 10, and a battery base 32 configured to attach the two batteries 31formed at a rear of the leg portion 50. The main tool body 10 and a gearhead 20 may be generally of the same construction as that of the firstembodiment. Various members, components, etc. that are identical to thatof the first embodiment are indicated by the same reference numerals,and a respective description thereof will be omitted.

As shown in FIG. 41, a support protrusion 52 may be integrally formedwith the main body housing 11 to extend outwardly from the main bodyhousing 11. Also, the leg portion 50 may be tiltably connected to thesupport protrusion 52, i.e. such that the leg portion 50 may tilt and/orat least partially rotate to be positioned at an angle relative to themain body housing 11 of the electric tool 9 as shown in FIG. 40.Connection edges 50 a may be integrally formed at a front end of the legportion 50 such that the connection edges 50 a may be parallel to eachother to generally form a forked pattern and/or configuration. Thesupport protrusion 52 may be inserted between the connection edges 50 a.Next, the support protrusion 52 may be connected so as to allow relativerotation by a connection shaft portion 50 b provided between theconnection edges 50 a. Accordingly, the leg portion 50 may be connectedto the rear portion of the main tool body 10 to be tiltable in, forexample, the vertical direction. The connection portion described hereis illustrated in further detail in at least FIGS. 42, 45, and 46.

A support hole 52 b (not shown in the FIGS.) may be formed at a centerof the support protrusion 52 to extend there-through in the thicknessdirection of the electric tool 9 (i.e. the width-wise and/or horizontaldirection). In detail, the connection shaft portion 50 b may be insertedinto the support hole 52 b. Further, the connection shaft portion 50 bmay be generally formed as a cylinder, and be supported and/or held inplace at both ends, while in between both connection edges 50 a, by ascrew 53 inserted and screwed into an inner surface of the connectionshaft portion 50 b.

As shown in FIG. 42, two steel balls 52 a may be retained on each ofright-hand side and left-hand side surfaces of the support protrusion52, specifically such thatthe two steel balls 52 a may both be retainedon the same circular region while being mutually mutually deviated fromeach other by 180 degrees, i.e., retained at positions opposite eachother. The four steel balls 52 a in total may be held in place to emergefrom the surfaces of the support protrusion 52. Engagement plates 54 ofan annular configuration may be superimposed on the right and leftsurfaces of the support protrusion 52. The two engagement plates 54 maybe fixed to the connection edge 50 a and exhibit a degree of elasticityin the thickness direction of the connection edge 50 a.

Four circular holes (i.e. a first through fourth engagement holes 54 athrough 54 d) may be formed and positioned in each of the two engagementplates 54 on the same circle at, for example, equal intervals. Two steelballs 52 a on the support protrusion 52 may be inserted and/or fittedinto two engagement holes 54 a and 54 c (or 54 b and 54 d) of the fourengagement holes 54 a through 54 d, which may be deviated from eachother by 180 degrees, i.e., situated on opposite sides. The steel balls52 a may be formed with a specific elasticity and/or bias to be able toenter and/or be elastically fitted into the engagement holes 54 athrough 54 d due to the elasticity of the engagement plate 54.

In the configuration shown in FIGS. 39 and 41 through 44, the legportion 50 may be positioned, set and/or retained in generally straightand/or erect position where the leg portion 50 is positioned straightwith respect to the main tool body 10. As shown in FIG. 42, the erectposition of the leg portion 50 with respect to the main tool body 10 maybe held in place and/or otherwise maintained by steel balls 52 a whichmay be elastically fitted into the first engagement hole 54 a on thefront upper position and the third engagement hole 54 c on the rearlower position of the four engagement holes 54 a through 54 d. At thistime, the second engagement hole 54 b on the front lower position andthe fourth engagement hole 54 d on the rear upper position may be empty.

Alternatively, as shown in FIG. 40, when the leg portion 50 is upwardlyrotated (i.e. clockwise as seen in the drawing) by 90 degrees into abent position, both engagement plates 54 may be tilted and/or rotated inthe same direction by 90 degrees with the leg portion 50. As a result ofthe clockwise rotation by 90 degrees of the two engagement plates 54from the state shown in FIG. 42, the two steel balls 52 a may beelastically fitted into the second engagement hole 54 b, which isdisplaced downwardly rearwards and into the fourth engagement hole 54 ddisplaced upwardly forwards. The leg portion 50 may be held in placeand/or retained in the bent position, with respect to the main tool body10, due to the insertion and elastic fitting of the two steel balls 52 ainto the second and fourth engagement holes 54 b and 54 d.

Accordingly, the electric tool 9 of the ninth embodiment may include theleg portion 50 at the rear of the main tool body 10 to be capabletilting and/or bending from the erect position to the bent position.Similar to that shown and discussed for the first embodiment, thebattery base 32 may be formed at the rear of the leg portion 50 toextend primarily in the right-to-left direction. As shown in FIG. 9, thetwo battery attachment portions 30 may be formed on the rear surface ofthe battery base 32 and arranged horizontally, i.e. side-by-side. Thetwo battery attachment portions 30 may be electrically connected to themain tool body 10 by appropriate wiring (not shown in the FIGS.).Further, two separate 18V batteries 31 may be attached to thecorresponding two battery attachment portions 30. Similar to the firstembodiment, the attachment direction of the two 18V batteries 31 may bein a downward direction. The attached two 18V batteries 31 may beconnected in series to function as a power source with a combined totaloutput voltage of 36V.

Further, as shown in FIG. 44, the rear portion of the leg portion 50 maycontain the controller board C which is configured to control theelectric motor 12 in a method similar to that presented and discussedfor the other embodiments.

The electric tool 9 of the ninth embodiment may be constructed and/orconfigured as described above. Specifically, the leg portion 50 may beprovided at a rear of the main tool body 10 to be rotatable between anerect position and a bent position as discussed. Moreover, two 18Vbatteries 31 may be attached to the rear portion of the leg portion 50.Such a configuration as described may shorten a length of the electrictool 9 in the front-to-rear direction (i.e., longitudinal direction ofthe main tool body) by folding the leg portion 50 to a bent position.Thus, accommodation space for the electric tool 9 may be compact.Further, the electric tool 9 may be tilted and/or bent, as desired, by auser to operate in relatively compact and/or tight spaces.

Further, the electric tool 9 may be used in a space that is relativelysmall in the longitudinal direction to perform drilling operation whenthe leg portion 50 is folded to a bent position to, for example, makethe electric tool 9 compact in the longitudinal direction. Suchoperational flexibility as described here enhances the overall usabilityof the electric tool 9.

As disclosed in the above-described embodiments, two rechargeable 18Vbatteries may be used together as a power source with a total outputvoltage of 36V by, for example, connecting the two rechargeable 18Vbatteries in series. Such a power source as described here, i.e. two 18Vbatteries connected in series to provide a total system output voltageof 36V, may allow the electric tools shown in one or more of theabove-described embodiments to be relatively flexible in terms of powerrequirement, i.e. such that the electric tools may be powered by readilyavailable 18V batteries, rather than a single potentially scarce and/orexpensive 36V battery. As a result, the electric tools shown in theabove embodiments may demand a total system output voltage of 36V, butmay also be conveniently powered by two readily-available 18V connectedin series as described above, and thus enjoy greater operationalflexibility and cost-efficiency.

The above-described may be further modified. For example, the twobatteries 31 may be attached to a right-hand side and a left-hand sideof the main tool body 10 or to a right-hand side and a left-hand side ofthe gear head 20, provided that such a configuration does not negativelyimpact and/or interfere with how the main tool body 10 may be grasped byan operator. Also, although two 18V batteries 31 are attached to thecorresponding battery attachment portions 30 in the above-describedexamples, three or more batteries may be attached to, for example, acorresponding number of battery attachment portions. Further, while thebatteries are of a generally parallelepiped-shaped lithium ion batteryof the slide attachment type (i.e. a type in which only one surface suchas the upper surface U may be attached to the battery attachment portion30) in the above examples, the present invention may also be modified tobe applicable to a generally stick-shaped lithium ion battery of aninsertion type (i.e. a type in which a battery may be inserted into acorresponding battery receptacle configured with battery connectionterminals at a given depth). Further, the battery 31 as discussed in theabove-described embodiments may not be restricted solely to a lithiumion battery, and the present invention may be configured to alsoaccommodate various other types of batteries such as a nickel-cadmiumbattery, for example.

Further, while two 18V batteries 31 are used as the power source of theelectric motor 12 of a rated voltage of 36V in the above-describedembodiments, a plurality of batteries of a rated voltage connected inseries may be used as a power source of an electric motor. Such anelectric motor may be operated by an output voltage that corresponds tosum total of the rated voltage of the batteries.

Moreover, in addition to that presented and discussed in theabove-described embodiments, the electric motor 12 may be powered by anelectric battery of a rated voltage of 18V, where the two batteries 31may be electrically connected in parallel, rather than in a series.Connecting the batteries 31 in parallel may increase length of timeduring which the batteries 31 may power the electric tool 1 and/or theelectric tool 9.

Further, while the electric tool 1 and/or 9 may be referred to as an“angle drill” for a drilling operation in a relatively tight and/orsmall space, the present invention may also be applicable to an angleimpact screwdriver (i.e. an impact driver, an impact wrench) which maybe a screwdriver for screw tightening operation and which may contain animpact mechanism for applying an impact in the screw tighteningdirection.

(First Embodiment)

In the following, a first embodiment of the present invention will bedescribed in further detail with reference to FIGS. 47 through 53. InFIG. 47, reference numeral 110 denotes a disc grinder in correspondenceto an electric tool in accordance with the present invention. FIG. 48 isa cut-away view of the disc grinder 110, i.e. where the disc grinder 110is cut in half across an imaginary axis extending from a front to a rearof the disc grinder 110 as shown by the legend of FIG. 48. FIG. 49 is aplan view (i.e. a diagrammatical view), as seen from below, of the discgrinder shown in FIG. 47. FIG. 50 is a plan view, as seen from behind(i.e., the rear), of the disc grinder shown in FIG. 47. FIG. 51 is adetailed perspective view of a rechargeable battery 180 inserted intoand/or attached to a battery attachment portion through, for example,sliding. FIG. 52 is an enlarged plan view of portion (LII) of FIG. 49,illustrating a battery terminal connection portion. FIG. 53 is aconceptual circuit diagram illustrating the circuit structure of anelectric motor schematically and conceptually. Also, in the followingdetailed description, the disc grinder 110 will be further describedwith reference to the directions defined in the drawings.

Referring generally now to FIG. 47, the disc grinder 110 is shown inconnection with a first embodiment of the invention. In detail, the discgrinder 110 may be a type of hand-held electric tool adapted to machinewhile being held by the hand of a user. The disc grinder 110 may berelatively high-powered and supply electric power set at a voltage of,for example, 36 V. The rechargeable battery 180 may be attached to, forexample, a corresponding receptacle in the disc grinder 110 throughsliding to provide a power source to allow for the operation the discgrinder 110. The disc grinder 110 may be a two-handle type that theoperator uses with his or her both hands at, for example, a constructionand/or work site. In detail, the disc grinder 110 may have two handlesthat includes a handle portion 113 formed as a part of a grip housing112, and a head side grip 119 mounted to a mounting female screw portion521 of a gear head 151 (head housing 152). A left-half grip housing 112Aand a right-half grip housing 112B may be joined together to form thegrip housing 112.

The disc grinder 110 generally may include a housing 111, an electricmotor 132 encased within the housing 111 and a gear mechanism 153. Thehousing 111 may include the grip housing 112 and a motor housing 131,i.e. arranged sequentially when viewed from the rear of the disc grinder110. The grip housing 112 and the motor housing 131 may be connected toeach other, and configure a part of an exterior member of the discgrinder 110. Further, a gear head 151 may be attached to the front endof the motor housing 131 that is coupled with the grip housing 112 viagear housing cover 147. The grip housing 112 may be assembled from, forexample, multiple separate components made from resin. Further, anoperation switch 120, a drive controller 117, a power controller 118,and battery attachment portions 160 (160 a and 160 b) may be held inplace by the grip housing 112 from both right and left sides, and may beaccommodated in the grip housing 112. The right and left half moldingcomponents that constitute the grip housing 112 may be fastened to eachother by using screw bosses 169.

As shown in the FIGS., the grip housing 112 may be generally configuredas a loop. In detail, the grip housing 112 may have a handle portion 113shaped as a loop. Also, and as shown in FIGS. 47 through 49, the griphousing 112 may be generally formed in a ring-like configuration (i.e.,a loop configuration as described above) that extends in thefront-to-rear direction. In detail, the upper portion of the griphousing 112 may function as the handle portion 113 and/or in conjunctionwith the handle portion 113 to allow the disc grinder 110 to be, forexample, easily grasped by the hand of an operator prior to operation ofthe disc grinder 110. A flexible and/or rubberized material, such as anelastomer, may be attached to an outer, i.e. a peripheral, surface ofthe handle portion 113 handle portion 113 to, for example, provide aslip-resistant surface adapted to be easily grasped and/or held by thehand of an operator of the disc grinder 110. A rear side-connectingportion 114 may be formed and/or coupled with a rear section of thehandle portion 113 and may generally extend in the downward direction asshown in FIG. 47. Further, a front side-connecting portion 115 may beformed at and/or toward a front section of the handle portion 113 andgenerally extend downwards. A lower portion of the rear side connectingportion 114 and a lower portion of the front side connecting portion 115may attach and/or otherwise combine as a single continuous surface toform a lower connecting portion 116. The lower connecting portion 116,as described here, may constitute a lower portion of the grip housing112 that, as described earlier, may be shaped and/or configured as of aloop. Also, in an embodiment, the lower connecting portion 116 may beformed in an arc-shaped and/or curved configuration. Further, twobattery attachment portions 160 (160 a and 160 b), to be described infurther detail below, may be formed at and/or near the lower connectingportion 116.

A drive controller 117 may be incorporated at and/or included within thefront portion of the grip housing 112, where the drive controller 117may include various electrical components such as a shunt resistor and afield-effect transistor (FET) circuit controller 117. Further, the drivecontroller 117 may be electrically connected to, for example, brushes ofthe electric motor 132 such that the drive controller 117 may controlthe disc grinder 110. Moreover, a power controller 118 may be mounted inthe lower connecting portion 116, where the power controller 118 may beconfigured to control voltage, etc., of power supplied from therechargeable batteries 180 (180 a and 180 b) attached to the batteryattachment portions 160 (160 a and 160 b). Also, an operation switch 120may be provided on the handle portion 113.

The operation switch 120 may include a switch main body 121 and anoperation button 122, where the switch main body 121 may be contained inthe grip housing 112 and may be supported by the grip housing 112. In anembodiment, the switch main body 121 may be, for example, a contactswitch that is widely used. The operation button 122 may be supported bythe grip housing 112 such that the operation button 122 may move freelyin, for example, the generally vertical direction. A contact (not shownin the FIGS.) of the switch main body 121 may be activated through, forexample, depressing the operation button 122 while grasping the handleportion 113. In detail, the switch main body 121 may input a signal tothe drive controller 117 when the contact of the switch main body 121 isactivated. Further, the signal, as described here, may indicate whetherthe switch is in, for example, an activated or deactivated condition.Further, in an embodiment, the operation button 122 may be fabricatedwith a biasing spring (not shown in the FIGS.) that automatically allowsthe operation button 122 to return to, for example, a natural, i.e.non-depressed, position associated with a switch-off state when theoperation button 122 has not been depressed.

A gear change dial 123 may be located on the front portion of the handleportion 113 and on the upper portion of the handle portion 113. The gearchange dial 123 may be configured to set a rotational speed of theelectric motor through dialing, i.e. an operator may “dial-in” a desiredrotational speed of the electric motor 132 by adjusting the gear changedial 123 as needed. The gear change dial 123 may input a signal to thedrive controller 117 where such a signal may indicate attainment of aset operational speed. A rear bearing 141 may be provided at the frontend of this grip housing 112, and the rear bearing 141 may support themotor shaft 133 of the electric motor 132 described below. The rearbearing 141 may be supported by the grip housing 112.

A motor housing 131 may be connected to a front portion of the griphousing 112. In detail, the motor housing 131 may be formed from amolded resin component. The motor housing 131 may surround and thusprovide structural support to the electric motor 132, i.e. which may bepositioned inside the motor housing 131. The electric motor 132 may bepowered by electricity supplied by, for example, the rechargeablebatteries 180 to rotate the motor shaft 133. In detail, in anembodiment, the electric motor 132 may be a brush motor, i.e. a motorthat includes a stator 134, a rotor 135 and a commutator 136. The stator134 may be a permanent magnet supported at least in part by the motorhousing 131, rotor 135A laminated steel core (not shown in the FIGS.)may be wound one or more times with wire to generally form the rotor135. Further, in an embodiment, the motor shaft 133 may function as arotation shaft of and/or for the rotor 135. The rear bearing 141 and afront bearing 142 may both rotatably support the motor shaft 133 at botha rear and a front end of the motor shaft 133. A cooling fan 138 may belocated toward and/or at a front of the rotor 135 and also be mounted toand/or coupled with the motor shaft 133.

A gear housing cover 147 may support the front bearing 142. Further, apinion gear 145 may be provided at a front end of the motor shaft 133such that the motor shaft 133 may function as, for example, a type ofrotation shaft. In an embodiment, the pinion gear 145 may be a taperedbevel gear that may mesh with a bevel gear 154 of a gear mechanism 153as to be further described in detail below. As shown in at least FIGS. 1and 2, the motor shaft 133 may be configured to rotate about a phantomline X1 shaft 133 that extends lengthwise from a front to a rear of thedisc grinder 110. A gear head 151 may be connected to the front of themotor housing 131. In detail, the gear head 151 may include both a headhousing 152 and a gear mechanism 153. The head housing 152 may beconstructed from an aluminum casting. The head housing 152 may containthe gear mechanism 153 that may convert and/or transition between one ormore possible drive modes, i.e. rotation drive modes, of the motor shaft133.

This gear mechanism 153 may include and/or communicate with the bevelgear 154, which may interlink and/or mesh with the pinion gear 145mounted to and/or coupled with a front end of the motor shaft 133.Further, in an embodiment, bevel gear 154 may be positioned near and/orbe in contact with an output shaft 155 which may function as shaftaround with the bevel gear 154 may rotate. An upper bearing 157 and alower bearing 158 may rotatably support the output shaft 155. The headhousing 152 may support both the upper bearing 157 and the lower bearing158. The lower end of the output shaft 155 may be formed as a mountingportion 156 that may allow for mounting of a tool accessory BB, such asa grind stone, that may be suitable to grind and/or machine a surface asneeded. In detail, the mounting portion 156 may correspond to a toolaccessory retaining portion.

Reference numeral 159 indicates a gear stopper that may regulate therotation of the output shaft 155. In FIG. 48, a phantom line X2indicates the rotation axis of the output shaft 155. A mounting femalescrew portion 521 for mounting a head side grip 119 may be formed onboth right and left side surfaces of the head housing 152. A mountingmale screw portion (not shown in the FIGS.) may be formed on the headside grip 119 to be threaded into the mounting female screw portion 521.Accordingly, the head side grip 119 may be mounted to the gear head 151.

Next, the two battery attachment portions 160 (160 a and 160 b) providedon the lower connecting portion 116 of the grip housing 112 will bedescribed in further detail. The two battery attachment portions 160 aand 160 b may be formed on and/or near the lower connecting portion 116of the grip housing 112. Also, in an embodiment, the two batteryattachment portions 160 a and 160 b may be formed at a part of the loopconfiguration of the grip housing 112 that includes the handle portion113. As initially described earlier, the lower connecting portion 116 ofthe grip housing 112 may form a portion of the loop configuration. Therechargeable batteries 180 a and 180 b may be slid into and thusrespectively attached to their corresponding battery attachment portions160 a and 160 b.

As shown in FIG. 51, the rechargeable batteries 180 a and 180 b may begeneral-purpose rechargeable batteries 180 which supply a voltage of,for example, 18 V. The rechargeable batteries 180 may be configured toaccommodate attachment via sliding, i.e. as described above, to thusattach to the battery attachment portions 160 by sliding. Thus, astructure for sliding attachment and a structure for effectingelectrical connection may be formed on an upper surface (i.e., aconnection terminal arrangement surface) of the rechargeable batteries180. In detail, as shown in FIG. 51, a pair of slide guide portions 181and 182 may be formed on the upper surface of the rechargeable batteries180 to assist in sliding attachment to the battery attachment portions160 as described here. Further, a positive-pole terminal 183, anegative-pole terminal 184 and a signal terminal 185 may be provided onan upper surface of the rechargeable batteries 180 to allow for anelectrical connection generally between the rechargeable batteries 180and the disc grinder 110 as needed. Further, a male hook 187 may beprovided on an upper surface of each battery 180, i.e. of therechargeable batteries 180, and the male hook 187 hold the rechargeablebatteries 180 in an engaged position with the battery attachmentportions 160 when, for example, the rechargeable batteries 180 areconnected electrically to the battery attachment portions 160 throughsliding.

A pushbutton 188 may be provided on a side where the rechargeablebatteries 180 may be detached (see FIG. 50, etc.) for operating the malehook 187. In detail, the pushbutton 188 may be connected to the malehook 187. For example an operator may depress the pushbutton 188 using afinger to cause the male hook 187 to either disengage or engage therechargeable battery 180 with a corresponding attachment portion 160 asdesired. Accordingly, the pushbutton may be depressed to disengageand/or detach the rechargeable battery 180 from the battery attachmentportion 160 battery 180 portion 160. Referring now to FIG. 51, referenceletter L FIG. 51 indicates a longitudinal length of the rechargeablebattery 180; reference letter W FIG. 51 indicates a length in a widthdirection of the rechargeable battery 180 and reference letter H FIG. 51indicates a length in a height direction of the rechargeable battery180. Further, in an embodiment, the rechargeable battery 180 may haveexternal dimensions substantially as follows: the length LL in thelongitudinal direction>the width WW in the width direction>the height HHin the height direction.

Next, the battery attachment portion 160 to which the rechargeablebattery 180 may be attached by sliding will be described in furtherdetail. As shown in FIGS. 49 and 52, the battery attachment portion 160may have a corresponding structure allowing the rechargeable battery 180to be attached thereto by sliding to electrically connect therechargeable battery 180 to the battery attachment portion 160 and/orother various components of the disc grinder 110 as needed.

As shown in FIG. 49, the battery attachment portion 160 has a pair ofslide guide receiving portions 161 and 162 as a structure configured toattach the battery 180 to the battery attachment portion 160 throughsliding as described earlier. As shown in FIG. 52, the batteryattachment portion 160 has a battery terminal connection portion 600that includes the positive-pole terminal 163, the negative-pole terminal164 and the signal terminal 165, as structures that may allow for anelectrical connection, generally between the battery 180 and the discgrinder 110. As shown in FIG. 49, when the rechargeable battery 180 isattached to the battery attachment portion 160 through sliding, therechargeable battery 180 may engage and/or interlock with the batteryattachment portion 160. In detail, a female portion (recess) 166 may beformed in the battery attachment portion 160, and the male hook 187 ofthe rechargeable battery 180 may thus insert into to engage with thefemale portion 166 as described here.

In FIG. 49, a phantom line X3 indicates an axis along which therechargeable battery 180 a may attach to the first battery attachmentportion 160 a by sliding. Further, in FIG. 49, a phantom line X4indicates an axis along which the rechargeable battery 180 b may attachto the second battery attachment portion 160 b by sliding. The first andsecond battery attachment portions 160 a and 160 b may include thestructure of the battery attachment portion 160 described above. Theaxis X3 and the axis X4 may be parallel to each other. Thus, the batteryattachment portions 160 a and 160 b of the first embodiment may beattached on the lower connection portion 116 of the grip housing 112 soas to allow the two rechargeable batteries 180 a and 180 b to beattached by sliding in parallel.

More specifically, the first battery attachment portion 160 a and thesecond battery attachment portion 160 b may be arranged in a parallelwhile also being deviated, i.e. in relation to each other, in thefront-rear direction with respect to the lower connecting portion 116.Both of the first and second battery attachment portions 160 a and 160 bmay be configured to be attached to the rechargeable batteries 180 a and180 b by sliding the rechargeable batteries 180 a and 180 b from rightto left, as shown by the legend in FIG. 49. In detail, the first andsecond battery attachment portions 160 a and 160 b may be configured tobe attached to the rechargeable batteries 180 a and 180 b by sliding therechargeable batteries 180 a and 180 b in the same direction, i.e. fromright to left, and in parallel. The controllers 117 and 118 may controlthe rechargeable batteries 180 a and 180 b attached to the first andsecond battery attachment portions 160 a and 160 b. In detail, as shownin the conceptual circuit diagram of FIG. 53, the drive controller 117and the power controller 118 may control the rotational drive of theelectric motor 132 of the disc grinder 110.

In detail, the drive controller 117 and the power controller 118 mayreceive input signals from the operation switch 120 and the shuntresistor 171 (i.e., a part of the drive controller 117), and send outputsignals to the FET circuit 172 (part of the drive controller 117). Thus,the drive controller 117 and the power controller 118 may control therotational drive of the electric motor 132. In detail, a circuitconnecting both the drive controller 117 and the power controller 118 tothe electric motor 132 may be designed such that the rechargeablebatteries 180 a and 180 b attached to the first and second batteryattachment portions 160 a and 160 b may be connected in, for example, aseries. Accordingly, power, i.e. electric current, supplied from therechargeable batteries 180 a and 180 b may be set such that the voltagesupplied via the first and second battery attachment portions 160 a and160 b is, for example: 18 V+18 V=36 V.

The disc grinder 110, generally in accordance to with the firstembodiment as described above, may provide advantages as to be furtherhere. Given that the disc grinder 110 of the first embodiment includestwo battery attachment portions 160 (160 a and 160 b), two rechargeablebatteries 180 (180 a and 180 b) may be attached to the disc grinder 110.In such a two-battery configuration as described, grinder 110 the discgrinder 110 may be configured to receive power, i.e. electric current,from the batteries 180 with a relatively high voltage and/or largesupply capacitance. As described earlier, power supplied from thebatteries 180 may reach a total system voltage of 36V, i.e. 18V+18V, byusing two general-purpose rechargeable batteries 180 that may supply 18Veach. In this configuration, the disc grinder 110 may be a high-powertype that requires high voltage for use, but may be powered bygeneral-purpose rechargeable batteries 180 in the configurationdescribed here.

In the disc grinder 110 of the first embodiment, the first and secondbattery attachment portions 160 a and 160 b may be formed on the lowerconnecting portion 116 of the grip housing 112, that may be generallyformed in a loop shape including the handle portion 113. In thisconfiguration, the weight of the rechargeable batteries 180 a and 180 battached to the battery attachment portions 160 a and 160 b may becentered on and/or around the handle portion 113 located above theattachment portions 160 a and 160 b. Such an even weight distribution ofthe batteries 180 may allow for the disc grinder 110 to be easilygrasped, lifted and held, i.e. in-hand by an operator, while machiningvia operation and/or rotation of the tool accessory BB. The disc grinder110 is held in hand for performing machining, and a load is applied to aworkpiece through the tool accessory BB. In comparison, a traditionallyconfigured disc grinder may feature an attachment portion for one ormore batteries at a rearmost section of the main tool body only, thuspotentially contributing to a weight imbalance during battery mountingand/or operation of the disc grinder. The current configuration ofplacing two batteries 180 in-sequence, as that disclosed by the firstembodiment, may substantially alleviate such weight-related balanceissues by distributing the weight and/or mass of the batteries 180evenly across the lower connecting portion 116, thus allowing the discgrinder to be easily grasped and/or handled by hand.

The battery attachment portions 160 a and 160 b may be configured suchthat axes X3 and X4 are parallel to each other. In detail, therechargeable batteries 180 a and 180 b may slide into and thus attach totheir corresponding battery attachment portions 160 a and 160 b alongthe axes X3 and X4. Accordingly, and as shown by FIG. 49, the length inan arrangement direction, i.e. from front to rear of the disc grinder110, of the rechargeable batteries 180 a and 180 b when arrangedside-by-side may be up to twice the length W in a width direction of therechargeable battery 180. In detail, the relatively shorter sides of therechargeable battery 180 may contact each other as shown in FIG. 49 togenerally minimize the volume occupied by the rechargeable batteries 180a and 180 b when arranged in parallel. Further, such a configuration asdescribed here may suppress deterioration of the maneuverability of thedisc grinder 110 when the disc grinder 110 is used for machining while,for example, held in hand.

In the first embodiment, the rechargeable batteries 180 a and 180 b maybe attached to the first and second battery attachment portions 160 aand 160 b along the same direction, i.e. from right to left. Further, inthe first and second battery attachment portions 160 a and 160 b, theslide attachment axes X3 and X4 may be parallel to each other asdiscussed above. In detail, the batteries 180 may be inserted into andmounted to and/or attached to their corresponding attachment portions160 in unison and/or in other various combinations, as needed, i.e. oneafter the other. Further, in an embodiment, the rechargeable batteries180 a and 180 b may be attached to the first and second batteryattachment portions 160 a and 160 b in the same direction, i.e., fromleft to right.

The mounting direction of the rechargeable battery 180 a with respect tothe first battery attachment portion 160 a may be from left to right.Alternatively, in an embodiment, the mounting direction of therechargeable battery 180 b with respect to the second battery attachmentportion 160 b may be from right to left. Also, in an embodiment, themounting direction of the rechargeable battery 180 a with respect to thefirst battery attachment portion 160 a may be from right to left.However, and in contrast to the mounting direction discussed above, themounting direction of the rechargeable battery 180 b, with respect tothe second battery attachment portion 160 b, may be from left to right.

(Second Embodiment)

Next, the second and third embodiments, which may be modifications ofthe first embodiment described above, will be described in furtherdetail with reference to FIGS. 54 through 59. In the second and thirdembodiments, only the arrangement of the battery attachment portions 160Differs from that of the disc grinder 110 of the first embodiment. Thus,portions of the disc grinder 110 which are formed substantially in thesame manner as in the first embodiment are indicated by like referencenumerals in the drawings, and a description thereof will be omitted.

First, a disc grinder 110A according to the second embodiment will bedescribed. FIG. 54 illustrates a side view of the disc grinder 110A ofthe second embodiment. FIG. 55 is a plan view, as seen from below, ofthe disc grinder 110A shown in FIG. 54. FIG. 56 is a plan view, as seenfrom behind, of the disc grinder 110A shown in FIG. 54. As shown inFIGS. 54 through 56, the battery attachment portions 160 A of the secondembodiment may also be arranged on the lower connecting portion 116 ofthe grip housing 112 i.e. same as the battery attachment portions 160 ofthe first embodiment.

In further detail, a first battery attachment portion 160Aa and a secondbattery attachment portions 160Ab may be arranged in parallel and alsomay be deviated in the right-left direction with respect to the lowerconnecting portion 116. Both the rechargeable batteries 180 a and 180 bmay be configured to attach to and/or connect with the first and secondbattery attachment portions 160Aa and 160Ab by sliding from rear-tofront, i.e. the rechargeable batteries 180 a and 180 b may be configuredto slide in the same direction, parallel each other, to attach to thefirst and second battery attachment portions 160Aa and 160Ab. The firstand second battery attachment portions 160Aa and 160Ab may be locatedsymmetrically with respect to the axis X1 along which the motor shaft133 extends with respect to the grip housing 112. Further, each batterymay be positioned symmetrically on either side of the axis X1. As shownin FIG. 54, reference numeral 118A indicates a power controller.

The disc grinder 110A of the second embodiment may be configured toprovide the same effect as the disc grinder 110 of the first embodiment,i.e. allowing for an operator to grasp and maneuver the disc grinder110A as may be needed for machining. Also, and in connection with thesecond embodiment for the disc grinder 110A, two rechargeable batteries180 (180 a and 180 b) may be attached through two battery attachmentportions 160 A (160Aa and 160Ab). In this configuration, power suppliedto operate the disc grinder 110A may have relatively high voltage and/orlarge supply capacitance. In detail, power supplied, i.e. electriccurrent, may be reach total 36V by using two general-purposerechargeable batteries 180 that may each supply 18V. In thisconfiguration, the disc grinder 110A may be a high-powered type thatrequires relatively high voltage while using general-purposerechargeable batteries 180.

Further, in the disc grinder 110A of the second embodiment, the twobattery attachment portions 160Aa and 160Ab may be respectively arrangedat positions symmetrical with respect to the axis X1 of the motor shaft(not shown in the FIGS.) with respect to the grip housing 112. Such aconfiguration as described here may evenly distribute the weight and/ormass of the rechargeable batteries 180 a and 180 b attached to the discgrinder 110A to, for example, suppress deterioration in themaneuverability of the disc grinder 110 when the disc grinder 110 isused for machining operation while held by hand.

Also in the disc grinder 110A of the second embodiment, the first andsecond battery attachment portions 160Aa and 160Ab may be formed on thelower connecting portion 116 of the grip housing 112. In thisconfiguration, the weight of the rechargeable batteries 180 a and 180 battached to the battery attachment portions 160Aa and 160Ab may becentered on and/or around the handle portion 113 located above theattachment portions 160Aa and 160Ab. Accordingly, the weight of thebatteries 180 a and 180 b may be effectively counterbalanced by anoperator who may grasp the handle portion 113 to maneuver the discgrinder 110A to, for example, suppress deterioration in themaneuverability of the disc grinder 110A.

The battery attachment portions 160Aa and 160Ab may be configured suchthat the axes X3 and X4 are parallel to each other. In detail, the axesX3 and X4 indicate the directions in which the rechargeable batteries180 a and 180 b may be attached to the battery attachment portions 160Aaand 160Ab by sliding. Thus, the length in the direction of arrangementof the rechargeable batteries 180 a and 180 b, when arranged side byside, may be up to twice the length W in the width direction of therechargeable battery 180. In detail, the relatively shorter lengths ofthe external dimensions of the rechargeable battery 180 may bepositioned adjacent to one-another as shown in FIG. 55 to, for example,minimize the total volume occupied by the rechargeable batteries 180 aand 180 b, when arranged in parallel. Such a configuration as describedhere may suppress deterioration in the maneuverability of the discgrinder 110, when the disc grinder 110 is used for machining operationwhile held in hand.

When compared with the disc grinder 110 of the first embodiment, thepositions of the battery attachment portions 160Aa and 160Ab as shown inthe disc grinder 110A of the second embodiment may be slightly deviatedbackwards. Thus, the disc grinder 110 of the first embodiment may bepreferred when the disc grinder 110 may be used for machining operationapplying a significant load to the tool accessory BB. In contrast, thedisc grinder 110A of the second embodiment may be preferred when thedisc grinder 110 is used for machining operation applying a minimal loadto the tool accessory BB. Also in the second embodiment, the directionfor attaching the rechargeable batteries 180 a and 180 b to the firstand second battery attachment portions 160Aa and 160Ab through slidingmay be opposite to the direction shown in FIG. 55. Moreover, therelatively directions for attaching the rechargeable batteries 180 a and180 b may be the same, opposite to each other, and/or any combinationsof the same.

(Third Embodiment)

Next, a disc grinder 110B in accordance with the third embodiment willbe described in further detail. FIG. 57 is a side view illustrating thedisc grinder 110B of the third embodiment. FIG. 58 is a plan view, asseen from below, of the disc grinder 110B shown in FIG. 57. FIG. 59 is aplan view, as seen from behind, of the disc grinder 110B shown in FIG.57. As shown in FIGS. 11 through 13, the battery attachment portions 160B of the third embodiment may also be arranged on the lower connectingportion 116 of the grip housing 112, the same as the battery attachmentportions 160 of the first embodiment.

In further detail, a first battery attachment portion 160Ba and a secondbattery attachment portions 160Bb may be arranged in parallel and bedeviated in right-to-left direction with respect to the lower connectingportion 116. Nevertheless, the first battery attachment portion 160Baand the second battery attachment portion 160Bb may be arranged suchthat the connection terminal arrangement surfaces of the rechargeablebatteries 180 a and 180 b face each other. More particularly, the firstbattery attachment portion 160Ba and the second battery attachmentportion 160Bb may be positioned symmetrically with respect to the axisX1 along which the motor shaft (not shown in the FIGS.) extends, i.e.,where the first battery attachment portion 160Ba is positioned on oneside of the motor shaft and the second battery attachment portion 160Bbis positioned on the other side of the motor shaft, opposite to thefirst battery attachment portion 160Ba. In the FIGS., reference numeral118A indicates a power controller. In this configuration, the firstbattery attachment portion 160Ba and the second battery attachmentportion 160Bb may be arranged such that the lower connecting portion 116of the grip housing 112 may be held between the connection terminalarrangement surfaces of the rechargeable batteries 180 a and 180 b.

Referring generally now to FIG. 58, the first battery attachment portion160Ba and the second battery attachment portion 160Bb may be positionedside-by-side, where each battery attachment portions 160Ba and 160Bb maybe configured to receive and/or attach to the rechargeable batteries 180a and 180 b, respectively. Further, as shown in FIG. 59, an intermediateconnecting portion 167B may be provided between the first batteryattachment portion 160Ba and the second battery attachment portion160Bb. The intermediate connecting portion 167B contains the powercontroller 118B. Further, both the rechargeable batteries 180 a and 180b may be attached to the first battery attachment portion 160Ba and thesecond battery attachment portion 160Bb by sliding from rear to front.

The disc grinder 110B of the third embodiment may be configured toprovide substantially the same effect as the disc grinder 110A of thesecond embodiment, i.e. directed toward machining a surface etc. In thethird embodiment of the disc grinder 110B, the length, fromright-to-left, i.e. the direction in which the rechargeable batteries180 a and 180 b may be arranged and/or attached with their respectivebattery attachment portions 160 a and 160 b, may be added double thelength W in the height direction, i.e. from right-to-left, of therechargeable battery 180. Further, the relatively shorter dimensions ofthe external dimensions of the rechargeable battery 180 may be added tothe width of the disc grinder 110B as shown in FIG. 59. Such aconfiguration as described here may minimize a total volume occupied bythe disc grinder 110B and may suppress an increase of bulkiness of thedisc grinder 110B as may otherwise be caused by the rechargeablebatteries 180 a and 180 b when, for example, arranged in parallelbeneath the lower connecting portion 116 (not shown in FIG. 57). Thedisc grinder 110B of the third embodiment may include the intermediateconnecting portion 167B between the first battery attachment portion160Ba and the second battery attachment portion 160Bb. The intermediateconnecting portion 167B may contain the power controller 118B. Such aconfiguration as described here may suppress an increase in the totalvolume of the disc grinder 110B.

As compared with the disc grinder 110A of the second embodiment, thepositions of the battery attachment portions 160Ba and 160Bb, in thedisc grinder 110B of the third embodiment, may be slightly deviatedforwards. Thus, the disc grinder 110B may be preferable over the discgrinder 110A of the second embodiment, when, for instance, the discgrinder 110B may be used in a machining operation that requires theapplication of a substantial load to the tool accessory BB. Also in thethird embodiment, the direction for attaching the rechargeable batteries180 a and 180 b to the first and second battery attachment portions160Ba and 160Bb through sliding may be opposite to the direction asshown in FIG. 57. Further, the relative directions for attaching therechargeable batteries 180 a and 180 b may be the same, opposite to eachother and/or any combination of the same.

(Fourth Embodiment)

Next, a disc grinder 110C in accordance with the fourth embodiment willbe described in further detail. FIG. 60 illustrates a side view of thedisc grinder 110C of the fourth embodiment. FIG. 61 is a plan view, asseen from below, of the disc grinder 110C shown in FIG. 60. FIG. 62 is aplan view, as seen from behind, of the disc grinder 110C shown in FIG.60. Battery attachment portions 160 C of the fourth embodiment may belocated at various positions, where some positions may differ from thatshown for the battery attachment positions 60, 60A, 60B in connectionwith the first through third embodiments. Thus, the followingdescription will focus on the differences of the disc grinder 110C fromthe disc grinders 110, 110A, and 110B as described above. The portionsthat are formed substantially in the same manner as in theabove-described embodiments are indicated by the same reference numeralsin the FIGS., and a description thereof will be omitted.

The battery attachment portions 160, 160 a and 160 b of the firstthrough third embodiments may be arranged on the lower connectingportion 16 of the grip housing 112. However, and as shown in FIGS. 60through 62, the battery attachment portions 160 C of the fourthembodiment may be arranged on the motor housing 131 that supports theelectric motor 132. More particularly, as shown in FIGS. 61 and 62, thebattery attachment portions 160 C may be arranged on an intermediateconnecting portion 167C provided on, for example, an outer peripheralsurface of the motor housing 131. In accordance with the configurationshown by the fourth embodiment, the disc grinder 110C may include a griphousing 112C such that the lower connecting portion 116, as shown inconnection with embodiments one through three, may be eliminated fromthe grip housing 112.

A first battery attachment portion 160Ca and a second battery attachmentportion 160Cb may be positioned and/or arranged in parallel to bedeviated from each other in, for example, the right-to-left directionwith respect to the motor housing 131. In detail, the first batteryattachment portion 160Ca and the second battery attachment portion 160Cbmay be arranged on the intermediate connecting portion 167C such thatconnection terminal arrangement surfaces of the rechargeable batteries180 a and 180 b face toward each other. More specifically, the firstbattery attachment portion 160Ca and the second battery attachmentportion 160Cb may be arranged symmetrically with respect to the axis X1along which the motor shaft (not shown in the FIGS.) extends. In detail,the first battery attachment portion 160Ca may be arranged on one sideof the axis X1, whereas the second battery attachment portion 160Cb maybe arranged on the other side of the axis X1 and be positioned oppositeto, i.e. facing, the first battery attachment portion 160Ca. In such aconfiguration as described here, the first battery attachment portion160Ca and the second battery attachment portion 160Cb may be arrangedsuch that the motor housing 131 may be held between the connectionterminal arrangement surfaces of the rechargeable batteries 180 a and180 b.

Thus, when attaching the rechargeable batteries 180 a and 180 b to thefirst battery attachment portion 160Ca and the second battery attachmentportion 160Cb, the rechargeable batteries 180 a and 180 b may beinverted relative to an initial position such that the rechargeablebatteries 180 a and 180 b may face each other. The intermediateconnecting portion 167C may contain the power controller 118C. Further,the rechargeable batteries 180 a and 180 b may be both attached to thefirst and second battery attachment portions 160Ca and 160Cb,respectively, by sliding generally in the up-to-down direction, i.e.downwards from above.

The disc grinder 110C of the fourth embodiment may provide substantiallythe same function as the disc grinder 110B of the third embodimentdescribed above, i.e. in being directed to machine surfaces, etc. Indetail, the first and second battery attachment portions 160Ca and 160Cbof the disc grinder 110C in the fourth embodiment may be arranged inparallel and be adjacent to the motor housing 131. As a result, theweight of the disc grinder 110C with attached the rechargeable batteries180 a and 180 b may apply to the front thereof as compared with the discgrinders 110, 110A, and 110B of the first through third embodiments. Asa result of such an arrangement, the weight and/or mass of therechargeable batteries 180 a and 180 b may be evenly distributed across,for example, a center axis X1 that may extend across the disc grinder110C in a front-to-rear direction. Accordingly, the disc grinder 110Cwith an even weight distribution as discussed above, may be preferablewhen the disc grinder 110C is used for machining operation with asubstantial load applied to the tool accessory BB.

The rechargeable batteries 180 a and 180 b attached to the first andsecond battery attachment portions 160Ca and 160Cb may be arranged nearthe electric motor 132 that may be relatively heavy and/or massive.Thus, the close proximity of the rechargeable batteries 180 a and 180 bto the electric motor 132 may concentrate the weight of the disc grinder110C around a particular section and/or area, potentially to contributeto enhanced maneuverability and/or operability. Additionally, asgenerally similar to the disc grinder 11B of the third embodimentdescribed above, in the fourth embodiment of the disc grinder 110C, thelength in the direction in which the rechargeable batteries 180 a and180 b may be arranged right-to-left, i.e. with a shorter length of therechargeable batteries 180 a and 180 b positioned in the front-to-reardirection as shown in, for example, FIG. 60 battery 180. Further, theshortest dimensions among the external dimensions of the rechargeablebattery 180 may extend width wise from the disc grinder 110C, that isfrom left-to-right when viewing the disc grinder 110C from the rear asshown in FIG. 62. Such a configuration of the rechargeable batteries 180relative to the disc grinder 110C as a whole as described here maysuppress an increase of bulkiness of the disc grinder 110C, and may befurther noticed in comparison to the disc grinder 110B that may have therechargeable batteries 180 a and 180 b arranged in parallel.

The power controller 118C may be arranged in the intermediate connectingportion 167C to suppress an increase in the size of the disc grinder110C as a whole. Also in the fourth embodiment, the direction forattaching the rechargeable batteries 180 a and 180 b to the first andsecond battery attachment portions 160Ca and 160Cb through sliding maybe opposite the direction as shown. Further, the directions forattaching the rechargeable batteries 180 a and 180 b may be the same,opposite each other and/or any combination of the same.

(Fifth Embodiment)

Next, a disc grinder 110D in accordance with the fifth embodiment willbe described in further detail. FIG. 63 is a side view illustrating thedisc grinder 110D of the fifth embodiment. FIG. 64 is a plan view, asseen from above, of the disc grinder 110C shown in FIG. 63. FIG. 65 is aplan view, as seen from behind, of the disc grinder 110D shown in FIG.63. The disc grinder 110D shown is a tool to which an appropriate toolaccessory BB is attached for cutting, separation, etc.

Unlike the disc grinders 110, 110A, 110B, and 110C described above, thedisc grinder 110 OD may be referred to as a “one-handle type” discgrinder, i.e. which an operator may use by grasping and maneuvering thedisc grinder 110D with only one hand. Thus, unlike the disc grinders110, 110A, 110B, and 110C described above, the disc grinder 110D may beused for machining while the handle portion 113D is held only by onehand. Accordingly, the disc grinder 110D may be configured to excludethe grip housing 112 of the above embodiment. As shown in FIG. 63, theouter peripheral portion of the motor housing 131D may be formed as thehandle portion 113D, which handle portion 113D may be of a straightconfiguration.

In the disc grinder 110D of the fifth embodiment, portions ofsubstantially the same function as the disc grinder 110 of the firstembodiment are indicated by the same reference numerals with a letter“D” attached thereto. Thus, numeral 120D indicates an operation switch,numeral 122D indicates an operation button, numeral 152D indicates ahead housing, and symbol BB indicates a tool accessory, and so on. Thebattery attachment portions 160D of the fifth embodiment may be arrangedat a rear end of the disc grinder 110D. More particularly, a firstbattery attachment portion 160Da and a second battery attachment portion160Db may be arranged in parallel and deviated in the right-leftdirection with respect to a rear end extension portion 167D.

The rechargeable batteries 180 a and 180 b may both be attached to thefirst and second battery attachment portions 160Da and 160Db throughsliding in the up-to-down direction, i.e. downwards from above. Indetail, the rechargeable batteries 180 a and 180 b may be attached tothe first and second battery attachment portions 160Da and 160Db bysliding in the same direction and parallel to each other. The first andsecond battery attachment portions 160Da and 160Db may be arrangedsymmetrically, i.e. side-by-side, with respect to the extendingdirection of an axis X1 of a motor shaft 133D, where each the first andsecond battery attachment portions 160Da and 160Db may be orientedgenerally vertically as shown in FIG. 63. Reference numeral 118Dindicates the power controller. Also, in this embodiment, the discgrinder 110D may be configured to receive power supplied by therechargeable batteries 180 a and 180 b based on the conceptual circuitdiagram of FIG. 53 via the first and second battery attachment portions160Da and 160Db. Further, power, i.e. electric current, may beconfigured to be delivered with a pre-set voltage of, i.e.; 18 V+18 V=36V.

The disc grinder 110D of the fifth embodiment may produce the followingresults. According also to the disc grinder 110D, two rechargeablebatteries 180 (180 a and 180 b) may be attached through two batteryattachment portions 160D (60Da and 60Db). In this configuration, powersupply for using the disc grinder 110D may have high voltage and/orlarge supply capacitance to comply with request. In detail, supply powermay be attain 36V by using, for example, two general-purposerechargeable batteries 180 that may supply 18V. In the configuration asdescribed here, the disc grinder 110A may be a high-powered type thatrequires a relatively high voltage while using general-purposerechargeable batteries 180. Further, in the disc grinder 110D of thefifth embodiment, the two battery attachment portions 160Da and 160Dbare respectively arranged at positions symmetrical with respect to theaxis X1 of the motor shaft 133D. Such a symmetrical arrangement of thebattery attachment portions 160Da and 160Db may evenly distribute theweight and/or mass of the rechargeable batteries 180 a and 180 battached to the disc grinder 110D to, for example, suppressdeterioration in the maneuverability of the disc grinder 110D when thedisc grinder 110D may be used for machining while held by hand.

Also in connection with the fifth embodiment of the disc grinder 110D,the length in the direction in which the rechargeable batteries 180 aand 180 b may be arranged may be combined, to, for example, double thewidth, i.e. distance W (not shown in FIG. 64), when viewed in aright-to-left direction of the rechargeable battery 180. In detail, therelatively shorter (i.e. width) dimensions from among the externaldimensions of the rechargeable battery 180 may be combined to define,for example, a widest cross-section of the disc grinder 110D. Such aconfiguration and/or orientation as that described here may suppress anincrease of bulkiness of the disc grinder 110D as may be caused by therechargeable batteries 180 a and 180 b when, for example, arranged inparallel as shown in connection with one or more of the earlierdiscussed embodiments. Further, the configuration of the rechargeablebatteries 180 a and 180 b shown by the fifth embodiment here may alsosuppress deterioration in maneuverability when, for example, performinga machining with the disc grinder 110D by hand. Also in the fifthembodiment, the direction for attaching the rechargeable batteries 180 aand 180 b to the first and second battery attachment portions 160Da and160Db by sliding may be opposite the direction as shown. Further, thedirections for attaching the rechargeable batteries 180 a and 180 b maybe the same, opposite each other and/or any combinations of the same.

The electric tool in accordance with the present invention may not berestricted to a disc grinder as in the above-described embodiments. Forinstance, configuration, orientation and/or construction of thatdisclosed by the above embodiments may be incorporated and/or includedas appropriate into any other hand-held electric tool that may be heldby hand to complete, for example, a machining operation. For example,the above embodiments may be applicable to various other types ofhand-held electric tools such as a disc sander, a polisher, and amulti-tool for grinding, cutting, polishing, glazing, etc. Further, therechargeable batteries 180 a and 180 b as discussed in connection withthe above embodiments may be set to a voltage of 18 V. However, inother, alternative embodiments the voltage of the rechargeable batteriesmay be set to a voltage other than 18V. Rechargeable batteries (i.e.secondary batteries) designed for appropriate voltages such as 10 V and14 V may be used.

Moreover, power supplied from the two rechargeable batteries 180 a and180 b may be used not only for enhancing voltage, but also for enhancingsupply capacitance (i.e. a total recharging amount). Accordingly, thepresent invention may not be restricted to configurations and/orconstructions for enhancing the voltage of the power supplied from therechargeable batteries 180, but also to configurations and/orconstructions for enhancing the supply capacitance of the power suppliedfrom the rechargeable batteries 180. Also, the voltage of therechargeable batteries may not be restricted to that of the embodiments,but may be set at some other system-appropriate voltage such as 10 Vand/or 14 V.

In the above-described embodiments, the bevel gear 154 may be rotated bythe pinion gear 145 that is fixed to the motor shaft 133. As describedand/or shown by the FIGS., the angle made by the motor shaft 133,functioning the rotation shaft of the pinion gear 145, and the outputshaft 155 functioning the rotation shaft of the bevel gear 154 may beeach set to 90 degrees. Electric tools in accordance with theembodiments should not be construed restrictively as such aconfiguration, but the output shaft 155 may be driven via a plurality ofshafts from the motor shafts 133. Moreover, the output shaft 155 may bedriven by an appropriate swinging mechanism provided between the motorshaft 133 and the output shaft 155. In detail, in the electric toolaccording to the present invention, it may only be necessary for themotor shaft 133 to drive the output shaft 133 in an appropriate mode,where one or more appropriate modes may be used as necessary, such asrotation, swinging, reciprocation and/or other modes of driving.

What is claimed is:
 1. An electric grinder comprising: two batteryattachment portions to which rechargeable batteries are attachable bysliding; a motor housing; an electric motor disposed within the motorhousing and configured to rotate a motor shaft by electric powersupplied from the rechargeable batteries; a tool accessory retainingportion configured to be driven by the motor shaft; a grip housingshaped as a loop and disposed on a rear side of the motor housing; and adrive controller disposed within the grip housing, wherein the drivecontroller is arranged on an extension line of the motor shaft, and thetwo battery attachment portions are disposed at the loop grip housing.2. The electric grinder according to claim 1, wherein each of the twobattery attachment portions is configured such that a correspondingrechargeable battery is attachable to each battery attachment portion bysliding movement of the rechargeable battery from a left side or a rightside of each battery attachment portion.
 3. The electric grinderaccording to claim 1, wherein the grip housing comprises a left-halfgrip housing and a right-half grip housing that are joined together. 4.The electric grinder according to claim 1, further comprising a powercontroller disposed within the grip housing.
 5. The electric grinderaccording to claim 1, further comprising an operation switch forrotating the electric motor, wherein: the drive controller is arrangedbetween the electric motor and the operation switch.
 6. The electricgrinder according to claim 1, wherein each of the rechargeable batteriessupplies a voltage of 18 V, so that a voltage of 36 V can be supplied bythe rechargeable batteries.
 7. The electric grinder according to claim1, wherein an elastomer is attached to a handle portion that is a partof the grip housing.
 8. The electric grinder according to claim 1,wherein the motor housing and the grip housing are arranged along thelongitudinal direction of the motor shaft, the tool accessory retainingportion comprises an output shaft perpendicular to the longitudinaldirection of the motor shaft and the two battery attachment portions arearranged at the rear end of the loop of the grip housing in thelongitudinal direction of the motor shaft.
 9. An electric hand-heldgrinding tool, comprising two battery attachment portions to whichrechargeable batteries may be attached through sliding, an electricmotor configured to rotate a motor shaft by electric power supplied fromthe rechargeable batteries, and a tool accessory retaining portiondriven by the motor shaft, wherein the two battery attachment portionsare provided on a housing constituting an exterior member such that axesalong which the rechargeable batteries are attached through sliding arepositioned in parallel with each other, wherein each of the batteryattachment portions has a pair of slide guide receiving portions and asa structure configured to attach the battery to the battery attachmentportion through sliding such that a male hook of the rechargeablebattery engages with a female portion in this state and the rechargeablebattery in this state is locked to the battery attachment portion. 10.The electric hand-held grinding tool according to claim 9, wherein thehousing constituting the exterior member comprises a handle portionformed in a loop configuration and the battery attachment portions areprovided at a part of the loop configuration.
 11. The electric hand-heldgrinding tool according to claim 9, wherein the housing receives anelectric motor and a gear mechanism, the housing comprises a griphousing and a motor housing arranged sequentially from a rear end of thegrinding tool towards the front, the grip housing and the motor housingare connected to each other and configure a part of the exterior memberof the electric hand-held grinding tool, a gear head is attached to thefront end of the motor housing that is coupled with the grip housing viaa gear housing cover.
 12. The electric hand-held grinding tool accordingto claim 9, wherein the grip housing is generally configured in the loopconfiguration and comprises the handle portion that is shaped as a loopand extends in the front-to-rear direction, the upper portion of thegrip housing is formed as the handle portion, an elastomer isappropriately attached to an outer peripheral surface of the handleportion, a rear side-connecting portion is formed at a rear section ofthe handle portion and generally extends in the downward direction, afront side-connecting portion may be formed at a front section of thehandle portion and generally extend downwards, a lower portion of therear side connecting portion and a lower portion of the front sideconnecting portion are continuous with each other to form a lowerconnecting portion, such that the lower connecting portion constitutes alower portion of the grip housing that is shaped as a loop.
 13. Theelectric hand-held grinding tool according claim 12, wherein the twobattery attachment portions are formed at the lower connecting portion.14. The electric hand-held grinding tool according claim 12, wherein thetwo battery attachment portions are formed at a part of the loopconfiguration of the grip housing that includes the handle portion. 15.The electric hand-held grinding tool according claim 12, wherein thebattery attachment portions are arranged at the rear portion of thehandle portion.
 16. The electric hand-held grinding tool according toclaim 9, wherein the first battery attachment portion and the secondbattery attachment portion are arranged in a parallel and configured tobe attached to the rechargeable batteries by sliding the rechargeablebatteries from left to right or right to left.
 17. The electrichand-held grinding tool according to claim 9, wherein each of thebattery attachment portions has an attachment structure corresponding tothe rechargeable battery with a structure for attaching the rechargeablebattery thereto by sliding and a structure for electrically connectingthe rechargeable battery.